diff --git a/src/EmailLexer.php b/src/EmailLexer.php
index 28d631f..0db4d06 100644
--- a/src/EmailLexer.php
+++ b/src/EmailLexer.php
@@ -140,9 +140,7 @@ class EmailLexer extends AbstractLexer
     /**
      * The last matched/seen token.
      *
-     * @var Token<int, string>
-     * 
-     * @psalm-suppress NonInvariantDocblockPropertyType
+     * @var Token<int, string>|null
      */
     public Token|null $token;
 
diff --git a/src/EmailParser.php b/src/EmailParser.php
index b72a731..acb4d90 100644
--- a/src/EmailParser.php
+++ b/src/EmailParser.php
@@ -36,7 +36,7 @@ class EmailParser extends Parser
     protected function preLeftParsing(): Result
     {
         if (!$this->hasAtToken()) {
-            return new InvalidEmail(new NoLocalPart(), $this->lexer->token->value);
+            return new InvalidEmail(new NoLocalPart(), $this->lexer->token?->value);
         }
         return new ValidEmail();
     }
diff --git a/src/MessageIDParser.php b/src/MessageIDParser.php
index a80b01a..761667d 100644
--- a/src/MessageIDParser.php
+++ b/src/MessageIDParser.php
@@ -37,7 +37,7 @@ class MessageIDParser extends Parser
     protected function preLeftParsing(): Result
     {
         if (!$this->hasAtToken()) {
-            return new InvalidEmail(new NoLocalPart(), $this->lexer->token->value);
+            return new InvalidEmail(new NoLocalPart(), $this->lexer->token?->value);
         }
         return new ValidEmail();
     }
diff --git a/src/Parser.php b/src/Parser.php
index c007c49..993ac3f 100644
--- a/src/Parser.php
+++ b/src/Parser.php
@@ -37,7 +37,7 @@ abstract class Parser
         $this->lexer->setInput($str);
 
         if ($this->lexer->hasInvalidTokens()) {
-            return new InvalidEmail(new ExpectingATEXT("Invalid tokens found"), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT("Invalid tokens found"), $this->lexer->token?->value);
         }
 
         $preParsingResult = $this->preLeftParsing();
@@ -73,6 +73,6 @@ abstract class Parser
         $this->lexer->moveNext();
         $this->lexer->moveNext();
 
-        return !$this->lexer->token->isA(EmailLexer::S_AT);
+        return !$this->lexer->token?->isA(EmailLexer::S_AT);
     }
 }
diff --git a/src/Parser/Comment.php b/src/Parser/Comment.php
index 1f66577..1032ac3 100644
--- a/src/Parser/Comment.php
+++ b/src/Parser/Comment.php
@@ -31,15 +31,15 @@ class Comment extends PartParser
 
     public function parse(): Result
     {
-        if ($this->lexer->token->isA(EmailLexer::S_OPENPARENTHESIS)) {
+        if ($this->lexer->token?->isA(EmailLexer::S_OPENPARENTHESIS)) {
             $this->openedParenthesis++;
             if ($this->noClosingParenthesis()) {
-                return new InvalidEmail(new UnclosedComment(), $this->lexer->token->value);
+                return new InvalidEmail(new UnclosedComment(), $this->lexer->token?->value);
             }
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_CLOSEPARENTHESIS)) {
-            return new InvalidEmail(new UnOpenedComment(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_CLOSEPARENTHESIS)) {
+            return new InvalidEmail(new UnOpenedComment(), $this->lexer->token?->value);
         }
 
         $this->warnings[WarningComment::CODE] = new WarningComment();
@@ -58,10 +58,10 @@ class Comment extends PartParser
         }
 
         if ($this->openedParenthesis >= 1) {
-            return new InvalidEmail(new UnclosedComment(), $this->lexer->token->value);
+            return new InvalidEmail(new UnclosedComment(), $this->lexer->token?->value);
         }
         if ($this->openedParenthesis < 0) {
-            return new InvalidEmail(new UnOpenedComment(), $this->lexer->token->value);
+            return new InvalidEmail(new UnOpenedComment(), $this->lexer->token?->value);
         }
 
         $finalValidations = $this->commentStrategy->endOfLoopValidations($this->lexer);
@@ -78,7 +78,7 @@ class Comment extends PartParser
     private function warnEscaping(): bool
     {
         //Backslash found
-        if (!$this->lexer->token->isA(EmailLexer::S_BACKSLASH)) {
+        if (!$this->lexer->token?->isA(EmailLexer::S_BACKSLASH)) {
             return false;
         }
 
@@ -87,7 +87,7 @@ class Comment extends PartParser
         }
 
         $this->warnings[QuotedPart::CODE] =
-            new QuotedPart($this->lexer->getPrevious()->type, $this->lexer->token->type);
+            new QuotedPart($this->lexer->getPrevious()->type, $this->lexer->token?->type);
         return true;
     }
 
diff --git a/src/Parser/CommentStrategy/DomainComment.php b/src/Parser/CommentStrategy/DomainComment.php
index 339f06b..edbadec 100644
--- a/src/Parser/CommentStrategy/DomainComment.php
+++ b/src/Parser/CommentStrategy/DomainComment.php
@@ -23,7 +23,7 @@ class DomainComment implements CommentStrategy
     {
         //test for end of string
         if (!$lexer->isNextToken(EmailLexer::S_DOT)) {
-            return new InvalidEmail(new ExpectingATEXT('DOT not found near CLOSEPARENTHESIS'), $lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT('DOT not found near CLOSEPARENTHESIS'), $lexer->token?->value);
         }
         //add warning
         //Address is valid within the message but cannot be used unmodified for the envelope
diff --git a/src/Parser/CommentStrategy/LocalComment.php b/src/Parser/CommentStrategy/LocalComment.php
index 75cfa68..6efc337 100644
--- a/src/Parser/CommentStrategy/LocalComment.php
+++ b/src/Parser/CommentStrategy/LocalComment.php
@@ -24,7 +24,7 @@ class LocalComment implements CommentStrategy
     public function endOfLoopValidations(EmailLexer $lexer): Result
     {
         if (!$lexer->isNextToken(EmailLexer::S_AT)) {
-            return new InvalidEmail(new ExpectingATEXT('ATEX is not expected after closing comments'), $lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT('ATEX is not expected after closing comments'), $lexer->token?->value);
         }
         $this->warnings[CFWSNearAt::CODE] = new CFWSNearAt();
         return new ValidEmail();
diff --git a/src/Parser/DomainLiteral.php b/src/Parser/DomainLiteral.php
index 962b9fd..58fed93 100644
--- a/src/Parser/DomainLiteral.php
+++ b/src/Parser/DomainLiteral.php
@@ -40,14 +40,14 @@ class DomainLiteral extends PartParser
         $addressLiteral = '';
 
         do {
-            if ($this->lexer->token->isA(EmailLexer::C_NUL)) {
-                return new InvalidEmail(new ExpectingDTEXT(), $this->lexer->token->value);
+            if ($this->lexer->token?->isA(EmailLexer::C_NUL)) {
+                return new InvalidEmail(new ExpectingDTEXT(), $this->lexer->token?->value);
             }
 
             $this->addObsoleteWarnings();
 
             if ($this->lexer->isNextTokenAny(array(EmailLexer::S_OPENBRACKET, EmailLexer::S_OPENBRACKET))) {
-                return new InvalidEmail(new ExpectingDTEXT(), $this->lexer->token->value);
+                return new InvalidEmail(new ExpectingDTEXT(), $this->lexer->token?->value);
             }
 
             if ($this->lexer->isNextTokenAny(
@@ -58,21 +58,21 @@ class DomainLiteral extends PartParser
             }
 
             if ($this->lexer->isNextToken(EmailLexer::S_CR)) {
-                return new InvalidEmail(new CRNoLF(), $this->lexer->token->value);
+                return new InvalidEmail(new CRNoLF(), $this->lexer->token?->value);
             }
 
-            if ($this->lexer->token->isA(EmailLexer::S_BACKSLASH)) {
-                return new InvalidEmail(new UnusualElements($this->lexer->token->value), $this->lexer->token->value);
+            if ($this->lexer->token?->isA(EmailLexer::S_BACKSLASH)) {
+                return new InvalidEmail(new UnusualElements($this->lexer->token?->value), $this->lexer->token?->value);
             }
-            if ($this->lexer->token->isA(EmailLexer::S_IPV6TAG)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_IPV6TAG)) {
                 $IPv6TAG = true;
             }
 
-            if ($this->lexer->token->isA(EmailLexer::S_CLOSEBRACKET)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_CLOSEBRACKET)) {
                 break;
             }
 
-            $addressLiteral .= $this->lexer->token->value;
+            $addressLiteral .= $this->lexer->token?->value;
         } while ($this->lexer->moveNext());
 
 
@@ -189,7 +189,7 @@ class DomainLiteral extends PartParser
 
     private function addObsoleteWarnings(): void
     {
-        if (in_array($this->lexer->token->type, self::OBSOLETE_WARNINGS)) {
+        if (in_array($this->lexer->token?->type, self::OBSOLETE_WARNINGS)) {
             $this->warnings[ObsoleteDTEXT::CODE] = new ObsoleteDTEXT();
         }
     }
diff --git a/src/Parser/DomainPart.php b/src/Parser/DomainPart.php
index ac6fd35..e7d45d9 100644
--- a/src/Parser/DomainPart.php
+++ b/src/Parser/DomainPart.php
@@ -50,8 +50,8 @@ class DomainPart extends PartParser
             return $domainChecks;
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_AT)) {
-            return new InvalidEmail(new ConsecutiveAt(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_AT)) {
+            return new InvalidEmail(new ConsecutiveAt(), $this->lexer->token?->value);
         }
 
         $result = $this->doParseDomainPart();
@@ -69,7 +69,7 @@ class DomainPart extends PartParser
 
         $length = strlen($this->domainPart);
         if ($length > self::DOMAIN_MAX_LENGTH) {
-            return new InvalidEmail(new DomainTooLong(), $this->lexer->token->value);
+            return new InvalidEmail(new DomainTooLong(), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -79,13 +79,13 @@ class DomainPart extends PartParser
     {
         $prev = $this->lexer->getPrevious();
         if ($prev->isA(EmailLexer::S_DOT)) {
-            return new InvalidEmail(new DotAtEnd(), $this->lexer->token->value);
+            return new InvalidEmail(new DotAtEnd(), $this->lexer->token?->value);
         }
         if ($prev->isA(EmailLexer::S_HYPHEN)) {
             return new InvalidEmail(new DomainHyphened('Hypen found at the end of the domain'), $prev->value);
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_SP)) {
+        if ($this->lexer->token?->isA(EmailLexer::S_SP)) {
             return new InvalidEmail(new CRLFAtTheEnd(), $prev->value);
         }
         return new ValidEmail();
@@ -103,7 +103,7 @@ class DomainPart extends PartParser
             return $missingDomain;
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_OPENPARENTHESIS)) {
+        if ($this->lexer->token?->isA(EmailLexer::S_OPENPARENTHESIS)) {
             $this->warnings[DeprecatedComment::CODE] = new DeprecatedComment();
         }
         return new ValidEmail();
@@ -111,12 +111,12 @@ class DomainPart extends PartParser
 
     private function checkEmptyDomain(): Result
     {
-        $thereIsNoDomain = $this->lexer->token->isA(EmailLexer::S_EMPTY) ||
-            ($this->lexer->token->isA(EmailLexer::S_SP) &&
+        $thereIsNoDomain = $this->lexer->token?->isA(EmailLexer::S_EMPTY) ||
+            ($this->lexer->token?->isA(EmailLexer::S_SP) &&
                 !$this->lexer->isNextToken(EmailLexer::GENERIC));
 
         if ($thereIsNoDomain) {
-            return new InvalidEmail(new NoDomainPart(), $this->lexer->token->value);
+            return new InvalidEmail(new NoDomainPart(), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -124,11 +124,11 @@ class DomainPart extends PartParser
 
     private function checkInvalidTokensAfterAT(): Result
     {
-        if ($this->lexer->token->isA(EmailLexer::S_DOT)) {
-            return new InvalidEmail(new DotAtStart(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_DOT)) {
+            return new InvalidEmail(new DotAtStart(), $this->lexer->token?->value);
         }
-        if ($this->lexer->token->isA(EmailLexer::S_HYPHEN)) {
-            return new InvalidEmail(new DomainHyphened('After AT'), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_HYPHEN)) {
+            return new InvalidEmail(new DomainHyphened('After AT'), $this->lexer->token?->value);
         }
         return new ValidEmail();
     }
@@ -156,8 +156,8 @@ class DomainPart extends PartParser
             }
 
             if (
-                $this->lexer->token->isA(EmailLexer::S_OPENPARENTHESIS) ||
-                $this->lexer->token->isA(EmailLexer::S_CLOSEPARENTHESIS)
+                $this->lexer->token?->isA(EmailLexer::S_OPENPARENTHESIS) ||
+                $this->lexer->token?->isA(EmailLexer::S_CLOSEPARENTHESIS)
             ) {
                 $hasComments = true;
                 $commentsResult = $this->parseComments();
@@ -173,7 +173,7 @@ class DomainPart extends PartParser
                 return $dotsResult;
             }
 
-            if ($this->lexer->token->isA(EmailLexer::S_OPENBRACKET)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_OPENBRACKET)) {
                 $literalResult = $this->parseDomainLiteral();
 
                 $this->addTLDWarnings($tldMissing);
@@ -190,9 +190,9 @@ class DomainPart extends PartParser
                 return $FwsResult;
             }
 
-            $domain .= $this->lexer->token->value;
+            $domain .= $this->lexer->token?->value;
 
-            if ($this->lexer->token->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::GENERIC)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::GENERIC)) {
                 $tldMissing = false;
             }
 
@@ -201,7 +201,7 @@ class DomainPart extends PartParser
                 return $exceptionsResult;
             }
             $this->lexer->moveNext();
-        } while (!$this->lexer->token->isA(EmailLexer::S_EMPTY));
+        } while (!$this->lexer->token?->isA(EmailLexer::S_EMPTY));
 
         $labelCheck = $this->checkLabelLength(true);
         if ($labelCheck->isInvalid()) {
@@ -235,7 +235,7 @@ class DomainPart extends PartParser
         try {
             $this->lexer->find(EmailLexer::S_CLOSEBRACKET);
         } catch (\RuntimeException $e) {
-            return new InvalidEmail(new ExpectingDomainLiteralClose(), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingDomainLiteralClose(), $this->lexer->token?->value);
         }
 
         $domainLiteralParser = new DomainLiteralParser($this->lexer);
@@ -252,19 +252,19 @@ class DomainPart extends PartParser
      */
     protected function checkDomainPartExceptions(Token $prev, bool $hasComments): Result
     {
-        if ($this->lexer->token->isA(EmailLexer::S_OPENBRACKET) && $prev->type !== EmailLexer::S_AT) {
-            return new InvalidEmail(new ExpectingATEXT('OPENBRACKET not after AT'), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_OPENBRACKET) && $prev->type !== EmailLexer::S_AT) {
+            return new InvalidEmail(new ExpectingATEXT('OPENBRACKET not after AT'), $this->lexer->token?->value);
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_HYPHEN) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
-            return new InvalidEmail(new DomainHyphened('Hypen found near DOT'), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_HYPHEN) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
+            return new InvalidEmail(new DomainHyphened('Hypen found near DOT'), $this->lexer->token?->value);
         }
 
         if (
-            $this->lexer->token->isA(EmailLexer::S_BACKSLASH)
+            $this->lexer->token?->isA(EmailLexer::S_BACKSLASH)
             && $this->lexer->isNextToken(EmailLexer::GENERIC)
         ) {
-            return new InvalidEmail(new ExpectingATEXT('Escaping following "ATOM"'), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT('Escaping following "ATOM"'), $this->lexer->token?->value);
         }
 
         return $this->validateTokens($hasComments);
@@ -283,8 +283,8 @@ class DomainPart extends PartParser
             $validDomainTokens[EmailLexer::S_CLOSEPARENTHESIS] = true;
         }
 
-        if (!isset($validDomainTokens[$this->lexer->token->type])) {
-            return new InvalidEmail(new ExpectingATEXT('Invalid token in domain: ' . $this->lexer->token->value), $this->lexer->token->value);
+        if (!isset($validDomainTokens[$this->lexer->token?->type])) {
+            return new InvalidEmail(new ExpectingATEXT('Invalid token in domain: ' . $this->lexer->token?->value), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -292,13 +292,13 @@ class DomainPart extends PartParser
 
     private function checkLabelLength(bool $isEndOfDomain = false): Result
     {
-        if ($this->lexer->token->isA(EmailLexer::S_DOT) || $isEndOfDomain) {
+        if ($this->lexer->token?->isA(EmailLexer::S_DOT) || $isEndOfDomain) {
             if ($this->isLabelTooLong($this->label)) {
-                return new InvalidEmail(new LabelTooLong(), $this->lexer->token->value);
+                return new InvalidEmail(new LabelTooLong(), $this->lexer->token?->value);
             }
             $this->label = '';
         }
-        $this->label .= $this->lexer->token->value;
+        $this->label .= $this->lexer->token?->value;
         return new ValidEmail();
     }
 
diff --git a/src/Parser/DoubleQuote.php b/src/Parser/DoubleQuote.php
index 9295066..c78978c 100644
--- a/src/Parser/DoubleQuote.php
+++ b/src/Parser/DoubleQuote.php
@@ -36,19 +36,19 @@ class DoubleQuote extends PartParser
 
         $this->lexer->moveNext();
 
-        while (!$this->lexer->token->isA(EmailLexer::S_DQUOTE) && !$this->lexer->token->isA(EmailLexer::S_EMPTY)) {
-            if (isset($special[$this->lexer->token->type]) && $setSpecialsWarning) {
+        while (!$this->lexer->token?->isA(EmailLexer::S_DQUOTE) && !$this->lexer->token?->isA(EmailLexer::S_EMPTY)) {
+            if (isset($special[$this->lexer->token?->type]) && $setSpecialsWarning) {
                 $this->warnings[CFWSWithFWS::CODE] = new CFWSWithFWS();
                 $setSpecialsWarning = false;
             }
-            if ($this->lexer->token->isA(EmailLexer::S_BACKSLASH) && $this->lexer->isNextToken(EmailLexer::S_DQUOTE)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_BACKSLASH) && $this->lexer->isNextToken(EmailLexer::S_DQUOTE)) {
                 $this->lexer->moveNext();
             }
 
             $this->lexer->moveNext();
 
-            if (!$this->escaped() && isset($invalid[$this->lexer->token->type])) {
-                return new InvalidEmail(new ExpectingATEXT("Expecting ATEXT between DQUOTE"), $this->lexer->token->value);
+            if (!$this->escaped() && isset($invalid[$this->lexer->token?->type])) {
+                return new InvalidEmail(new ExpectingATEXT("Expecting ATEXT between DQUOTE"), $this->lexer->token?->value);
             }
         }
 
@@ -60,7 +60,7 @@ class DoubleQuote extends PartParser
         }
 
         if (!$this->lexer->isNextToken(EmailLexer::S_AT) && !$prev->isA(EmailLexer::S_BACKSLASH)) {
-            return new InvalidEmail(new ExpectingATEXT("Expecting ATEXT between DQUOTE"), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT("Expecting ATEXT between DQUOTE"), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -72,15 +72,15 @@ class DoubleQuote extends PartParser
 
         if ($this->lexer->isNextToken(EmailLexer::GENERIC) && $previous->isA(EmailLexer::GENERIC)) {
             $description = 'https://tools.ietf.org/html/rfc5322#section-3.2.4 - quoted string should be a unit';
-            return new InvalidEmail(new ExpectingATEXT($description), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT($description), $this->lexer->token?->value);
         }
 
         try {
             $this->lexer->find(EmailLexer::S_DQUOTE);
         } catch (\Exception $e) {
-            return new InvalidEmail(new UnclosedQuotedString(), $this->lexer->token->value);
+            return new InvalidEmail(new UnclosedQuotedString(), $this->lexer->token?->value);
         }
-        $this->warnings[QuotedString::CODE] = new QuotedString($previous->value, $this->lexer->token->value);
+        $this->warnings[QuotedString::CODE] = new QuotedString($previous->value, $this->lexer->token?->value);
 
         return new ValidEmail();
     }
diff --git a/src/Parser/FoldingWhiteSpace.php b/src/Parser/FoldingWhiteSpace.php
index b6ded56..df51b8e 100644
--- a/src/Parser/FoldingWhiteSpace.php
+++ b/src/Parser/FoldingWhiteSpace.php
@@ -37,16 +37,16 @@ class  FoldingWhiteSpace extends PartParser
             return $resultCRLF;
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_CR)) {
-            return new InvalidEmail(new CRNoLF(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_CR)) {
+            return new InvalidEmail(new CRNoLF(), $this->lexer->token?->value);
         }
 
         if ($this->lexer->isNextToken(EmailLexer::GENERIC) && !$previous->isA(EmailLexer::S_AT)) {
-            return new InvalidEmail(new AtextAfterCFWS(), $this->lexer->token->value);
+            return new InvalidEmail(new AtextAfterCFWS(), $this->lexer->token?->value);
         }
 
-        if ($this->lexer->token->isA(EmailLexer::S_LF) || $this->lexer->token->isA(EmailLexer::C_NUL)) {
-            return new InvalidEmail(new ExpectingCTEXT(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_LF) || $this->lexer->token?->isA(EmailLexer::C_NUL)) {
+            return new InvalidEmail(new ExpectingCTEXT(), $this->lexer->token?->value);
         }
 
         if ($this->lexer->isNextToken(EmailLexer::S_AT) || $previous->isA(EmailLexer::S_AT)) {
@@ -60,17 +60,17 @@ class  FoldingWhiteSpace extends PartParser
 
     protected function checkCRLFInFWS(): Result
     {
-        if (!$this->lexer->token->isA(EmailLexer::CRLF)) {
+        if (!$this->lexer->token?->isA(EmailLexer::CRLF)) {
             return new ValidEmail();
         }
 
         if (!$this->lexer->isNextTokenAny(array(EmailLexer::S_SP, EmailLexer::S_HTAB))) {
-            return new InvalidEmail(new CRLFX2(), $this->lexer->token->value);
+            return new InvalidEmail(new CRLFX2(), $this->lexer->token?->value);
         }
 
         //this has no coverage. Condition is repeated from above one
         if (!$this->lexer->isNextTokenAny(array(EmailLexer::S_SP, EmailLexer::S_HTAB))) {
-            return new InvalidEmail(new CRLFAtTheEnd(), $this->lexer->token->value);
+            return new InvalidEmail(new CRLFAtTheEnd(), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -82,6 +82,6 @@ class  FoldingWhiteSpace extends PartParser
             return false;
         }
 
-        return in_array($this->lexer->token->type, self::FWS_TYPES);
+        return in_array($this->lexer->token?->type, self::FWS_TYPES);
     }
 }
diff --git a/src/Parser/IDLeftPart.php b/src/Parser/IDLeftPart.php
index 20707cf..03c1e0d 100644
--- a/src/Parser/IDLeftPart.php
+++ b/src/Parser/IDLeftPart.php
@@ -10,6 +10,6 @@ class IDLeftPart extends LocalPart
 {
     protected function parseComments(): Result
     {
-        return new InvalidEmail(new CommentsInIDRight(), $this->lexer->token->value);
+        return new InvalidEmail(new CommentsInIDRight(), $this->lexer->token?->value);
     }
 }
diff --git a/src/Parser/IDRightPart.php b/src/Parser/IDRightPart.php
index 47e5284..6f41c68 100644
--- a/src/Parser/IDRightPart.php
+++ b/src/Parser/IDRightPart.php
@@ -21,8 +21,8 @@ class IDRightPart extends DomainPart
             EmailLexer::S_LOWERTHAN => true,
         ];
 
-        if (isset($invalidDomainTokens[$this->lexer->token->type])) {
-            return new InvalidEmail(new ExpectingATEXT('Invalid token in domain: ' . $this->lexer->token->value), $this->lexer->token->value);
+        if (isset($invalidDomainTokens[$this->lexer->token?->type])) {
+            return new InvalidEmail(new ExpectingATEXT('Invalid token in domain: ' . $this->lexer->token?->value), $this->lexer->token?->value);
         }
         return new ValidEmail();
     }
diff --git a/src/Parser/LocalPart.php b/src/Parser/LocalPart.php
index d42873f..2cb54d9 100644
--- a/src/Parser/LocalPart.php
+++ b/src/Parser/LocalPart.php
@@ -36,12 +36,12 @@ class LocalPart extends PartParser
     {
         $this->lexer->startRecording();
 
-        while (!$this->lexer->token->isA(EmailLexer::S_AT) && !$this->lexer->token->isA(EmailLexer::S_EMPTY)) {
+        while (!$this->lexer->token?->isA(EmailLexer::S_AT) && !$this->lexer->token?->isA(EmailLexer::S_EMPTY)) {
             if ($this->hasDotAtStart()) {
-                return new InvalidEmail(new DotAtStart(), $this->lexer->token->value);
+                return new InvalidEmail(new DotAtStart(), $this->lexer->token?->value);
             }
 
-            if ($this->lexer->token->isA(EmailLexer::S_DQUOTE)) {
+            if ($this->lexer->token?->isA(EmailLexer::S_DQUOTE)) {
                 $dquoteParsingResult = $this->parseDoubleQuote();
 
                 //Invalid double quote parsing
@@ -51,8 +51,8 @@ class LocalPart extends PartParser
             }
 
             if (
-                $this->lexer->token->isA(EmailLexer::S_OPENPARENTHESIS) ||
-                $this->lexer->token->isA(EmailLexer::S_CLOSEPARENTHESIS)
+                $this->lexer->token?->isA(EmailLexer::S_OPENPARENTHESIS) ||
+                $this->lexer->token?->isA(EmailLexer::S_CLOSEPARENTHESIS)
             ) {
                 $commentsResult = $this->parseComments();
 
@@ -62,15 +62,15 @@ class LocalPart extends PartParser
                 }
             }
 
-            if ($this->lexer->token->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
-                return new InvalidEmail(new ConsecutiveDot(), $this->lexer->token->value);
+            if ($this->lexer->token?->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
+                return new InvalidEmail(new ConsecutiveDot(), $this->lexer->token?->value);
             }
 
             if (
-                $this->lexer->token->isA(EmailLexer::S_DOT) &&
+                $this->lexer->token?->isA(EmailLexer::S_DOT) &&
                 $this->lexer->isNextToken(EmailLexer::S_AT)
             ) {
-                return new InvalidEmail(new DotAtEnd(), $this->lexer->token->value);
+                return new InvalidEmail(new DotAtEnd(), $this->lexer->token?->value);
             }
 
             $resultEscaping = $this->validateEscaping();
@@ -102,8 +102,8 @@ class LocalPart extends PartParser
 
     protected function validateTokens(bool $hasComments): Result
     {
-        if (isset(self::INVALID_TOKENS[$this->lexer->token->type])) {
-            return new InvalidEmail(new ExpectingATEXT('Invalid token found'), $this->lexer->token->value);
+        if (isset(self::INVALID_TOKENS[$this->lexer->token?->type])) {
+            return new InvalidEmail(new ExpectingATEXT('Invalid token found'), $this->lexer->token?->value);
         }
         return new ValidEmail();
     }
@@ -125,7 +125,7 @@ class LocalPart extends PartParser
 
     private function hasDotAtStart(): bool
     {
-        return $this->lexer->token->isA(EmailLexer::S_DOT) && $this->lexer->getPrevious()->isA(EmailLexer::S_EMPTY);
+        return $this->lexer->token?->isA(EmailLexer::S_DOT) && $this->lexer->getPrevious()->isA(EmailLexer::S_EMPTY);
     }
 
     private function parseDoubleQuote(): Result
@@ -151,12 +151,12 @@ class LocalPart extends PartParser
     private function validateEscaping(): Result
     {
         //Backslash found
-        if (!$this->lexer->token->isA(EmailLexer::S_BACKSLASH)) {
+        if (!$this->lexer->token?->isA(EmailLexer::S_BACKSLASH)) {
             return new ValidEmail();
         }
 
         if ($this->lexer->isNextToken(EmailLexer::GENERIC)) {
-            return new InvalidEmail(new ExpectingATEXT('Found ATOM after escaping'), $this->lexer->token->value);
+            return new InvalidEmail(new ExpectingATEXT('Found ATOM after escaping'), $this->lexer->token?->value);
         }
 
         if (!$this->lexer->isNextTokenAny(array(EmailLexer::S_SP, EmailLexer::S_HTAB, EmailLexer::C_DEL))) {
diff --git a/src/Parser/PartParser.php b/src/Parser/PartParser.php
index 35418de..e672ea5 100644
--- a/src/Parser/PartParser.php
+++ b/src/Parser/PartParser.php
@@ -45,8 +45,8 @@ abstract class PartParser
 
     protected function checkConsecutiveDots(): Result
     {
-        if ($this->lexer->token->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
-            return new InvalidEmail(new ConsecutiveDot(), $this->lexer->token->value);
+        if ($this->lexer->token?->isA(EmailLexer::S_DOT) && $this->lexer->isNextToken(EmailLexer::S_DOT)) {
+            return new InvalidEmail(new ConsecutiveDot(), $this->lexer->token?->value);
         }
 
         return new ValidEmail();
@@ -57,6 +57,6 @@ abstract class PartParser
         $previous = $this->lexer->getPrevious();
 
         return $previous->isA(EmailLexer::S_BACKSLASH)
-            && !$this->lexer->token->isA(EmailLexer::GENERIC);
+            && !$this->lexer->token?->isA(EmailLexer::GENERIC);
     }
 }
diff --git a/tests/EmailValidator/EmailLexerTest.php b/tests/EmailValidator/EmailLexerTest.php
index ad0b07c..4af25e3 100644
--- a/tests/EmailValidator/EmailLexerTest.php
+++ b/tests/EmailValidator/EmailLexerTest.php
@@ -24,7 +24,7 @@ class EmailLexerTest extends TestCase
         $lexer->setInput($str);
         $lexer->moveNext();
         $lexer->moveNext();
-        $this->assertEquals($token, $lexer->token->type);
+        $this->assertEquals($token, $lexer->token?->type);
     }
 
     public function testLexerParsesMultipleSpaces()
@@ -33,9 +33,9 @@ class EmailLexerTest extends TestCase
         $lexer->setInput('  ');
         $lexer->moveNext();
         $lexer->moveNext();
-        $this->assertEquals(EmailLexer::S_SP, $lexer->token->type);
+        $this->assertEquals(EmailLexer::S_SP, $lexer->token?->type);
         $lexer->moveNext();
-        $this->assertEquals(EmailLexer::S_SP, $lexer->token->type);
+        $this->assertEquals(EmailLexer::S_SP, $lexer->token?->type);
     }
 
     /**
@@ -48,7 +48,7 @@ class EmailLexerTest extends TestCase
         $lexer->moveNext();
         $lexer->moveNext();
 
-        $this->assertEquals(EmailLexer::INVALID, $lexer->token->type);
+        $this->assertEquals(EmailLexer::INVALID, $lexer->token?->type);
     }
 
     public function invalidUTF8CharsProvider()
@@ -101,7 +101,7 @@ class EmailLexerTest extends TestCase
         $lexer->moveNext();
         $lexer->skipUntil(EmailLexer::S_HTAB);
         $lexer->moveNext();
-        $this->assertEquals(EmailLexer::S_HTAB, $lexer->token->type);
+        $this->assertEquals(EmailLexer::S_HTAB, $lexer->token?->type);
     }
 
     public function testLexerForUTF8()
@@ -110,9 +110,9 @@ class EmailLexerTest extends TestCase
         $lexer->setInput("áÇ@bar.com");
         $lexer->moveNext();
         $lexer->moveNext();
-        $this->assertEquals(EmailLexer::GENERIC, $lexer->token->type);
+        $this->assertEquals(EmailLexer::GENERIC, $lexer->token?->type);
         $lexer->moveNext();
-        $this->assertEquals(EmailLexer::GENERIC, $lexer->token->type);
+        $this->assertEquals(EmailLexer::GENERIC, $lexer->token?->type);
     }
 
     public function testLexerSearchToken()