diff --git a/Classes/Domain/Service/Mail/ReceiverMailReceiverPropertiesService.php b/Classes/Domain/Service/Mail/ReceiverMailReceiverPropertiesService.php
index 6097cde30..5ff8b573b 100644
--- a/Classes/Domain/Service/Mail/ReceiverMailReceiverPropertiesService.php
+++ b/Classes/Domain/Service/Mail/ReceiverMailReceiverPropertiesService.php
@@ -118,11 +118,11 @@ public function getReceiverName(): string
     protected function setReceiverEmails(): void
     {
         $emailArray = $this->getEmailsFromFlexForm();
-        $emailArray = $this->getEmailsFromFeGroup($emailArray, (int)$this->settings['receiver']['fe_group']);
-        $emailArray = $this->getEmailsFromBeGroup($emailArray, (int)$this->settings['receiver']['be_group']);
+        $emailArray = $this->getEmailsFromFeGroup($emailArray, (int)($this->settings['receiver']['fe_group'] ?? 0));
+        $emailArray = $this->getEmailsFromBeGroup($emailArray, (int)($this->settings['receiver']['be_group'] ?? 0));
         $emailArray = $this->getEmailsFromPredefinedEmail(
             $emailArray,
-            (string)$this->settings['receiver']['predefinedemail']
+            (string)($this->settings['receiver']['predefinedemail'] ?? '')
         );
         $emailArray = $this->overWriteEmailsWithTypoScript($emailArray);
         $emailArray = $this->getEmailFromDevelopmentContext($emailArray);
@@ -140,7 +140,7 @@ protected function setReceiverEmails(): void
      */
     protected function getEmailsFromFlexForm(): array
     {
-        if ((int)$this->settings['receiver']['type'] === self::RECEIVERS_DEFAULT) {
+        if ((int)($this->settings['receiver']['type'] ?? 0) === self::RECEIVERS_DEFAULT) {
             $mailRepository = ObjectUtility::getObjectManager()->get(MailRepository::class);
             $emailString = TemplateUtility::fluidParseString(
                 $this->settings['receiver']['email'],
@@ -161,7 +161,7 @@ protected function getEmailsFromFlexForm(): array
      */
     protected function getEmailsFromFeGroup(array $emailArray, int $uid): array
     {
-        if ((int)$this->settings['receiver']['type'] === self::RECEIVERS_FRONTENDGROUP && !empty($uid)) {
+        if ((int)($this->settings['receiver']['type'] ?? 0) === self::RECEIVERS_FRONTENDGROUP && !empty($uid)) {
             $userRepository = ObjectUtility::getObjectManager()->get(UserRepository::class);
             $users = $userRepository->findByUsergroup($uid);
             $emailArray = [];
@@ -186,7 +186,7 @@ protected function getEmailsFromFeGroup(array $emailArray, int $uid): array
      */
     protected function getEmailsFromBeGroup(array $emailArray, int $uid): array
     {
-        if ((int)$this->settings['receiver']['type'] === self::RECEIVERS_BACKENDGROUP && !empty($uid)) {
+        if ((int)($this->settings['receiver']['type'] ?? 0) === self::RECEIVERS_BACKENDGROUP && !empty($uid)) {
             /** @var BackendUserRepository $beUserRepository */
             $beUserRepository = ObjectUtility::getObjectManager()->get(BackendUserRepository::class);
             $query = $beUserRepository->createQuery();
@@ -217,7 +217,7 @@ protected function getEmailsFromBeGroup(array $emailArray, int $uid): array
      */
     protected function getEmailsFromPredefinedEmail(array $emailArray, string $predefinedString): array
     {
-        if ((int)$this->settings['receiver']['type'] === self::RECEIVERS_PREDEFINED && !empty($predefinedString)) {
+        if ((int)($this->settings['receiver']['type'] ?? 0) === self::RECEIVERS_PREDEFINED && !empty($predefinedString)) {
             $receiverString = TypoScriptUtility::overwriteValueFromTypoScript(
                 '',
                 $this->configuration['receiver.']['predefinedReceiver.'][$predefinedString . '.'],
diff --git a/Classes/Tca/ShowFormNoteEditForm.php b/Classes/Tca/ShowFormNoteEditForm.php
index 67604e4ba..bd5e5f936 100644
--- a/Classes/Tca/ShowFormNoteEditForm.php
+++ b/Classes/Tca/ShowFormNoteEditForm.php
@@ -219,7 +219,8 @@ protected function getRelatedFormUid(): int
     {
         $flexFormArray = (array)$this->data['databaseRow']['pi_flexform']['data']['main']['lDEF'];
         $formUid = (int)$flexFormArray['settings.flexform.main.form']['vDEF'][0];
-        $formUid = $this->getLocalizedFormUid($formUid, (int)$this->data['databaseRow']['sys_language_uid'][0]);
+        $language = (int)($this->data['databaseRow']['sys_language_uid'][0] ?? $this->data['databaseRow']['sys_language_uid'] ?? 0);
+        $formUid = $this->getLocalizedFormUid($formUid, $language);
         return $formUid;
     }
 
diff --git a/Classes/Utility/FrontendUtility.php b/Classes/Utility/FrontendUtility.php
index 8cb501d81..11ccaa40d 100644
--- a/Classes/Utility/FrontendUtility.php
+++ b/Classes/Utility/FrontendUtility.php
@@ -188,7 +188,7 @@ public static function getPropertyFromLoggedInFrontendUser(string $propertyName
     public static function getDomainFromUri(string $uri): string
     {
         $uriParts = parse_url($uri);
-        return (string)$uriParts['host'];
+        return (string)($uriParts['host'] ?? '');
     }
 
     /**
diff --git a/ext_emconf.php b/ext_emconf.php
index 5669d4d4b..c612970f3 100644
--- a/ext_emconf.php
+++ b/ext_emconf.php
@@ -9,7 +9,7 @@
         and easy to use mailform extension with a lots of features
         (spam prevention, marketing information, optin, ajax submit, diagram analysis, etc...)',
     'category' => 'plugin',
-    'version' => '9.0.1',
+    'version' => '9.0.2',
     'state' => 'beta',
     'author' => 'Powermail Development Team',
     'author_email' => 'service@in2code.de',