diff --git a/Classes/Authentication/KeyAuthenticationProvider.php b/Classes/Authentication/KeyAuthenticationProvider.php
index 3825f0c..274ba95 100644
--- a/Classes/Authentication/KeyAuthenticationProvider.php
+++ b/Classes/Authentication/KeyAuthenticationProvider.php
@@ -19,11 +19,11 @@ class KeyAuthenticationProvider
      * @param $key
      * @return bool
      */
-    public function hasValidKey($key)
+    public function hasValidKey($key): bool
     {
         $config = Configuration::getExtConfiguration();
         return trim($config['apiKey']) === trim($key);
     }
 
 
-}
\ No newline at end of file
+}
diff --git a/Classes/Middleware/ZabbixClient.php b/Classes/Middleware/ZabbixClient.php
index c2f85e3..4f38df4 100644
--- a/Classes/Middleware/ZabbixClient.php
+++ b/Classes/Middleware/ZabbixClient.php
@@ -69,7 +69,7 @@ private function processRequest(ServerRequestInterface $request)
             return $response->withStatus(403, 'Not allowed');
         }
 
-        $key = $request->getParsedBody()['key'] ?? $request->getQueryParams()['key'] ?? null;
+        $key = $request->getParsedBody()['key'] ?? $request->getQueryParams()['key'] ?? '';
         $keyAuthenticationProvider = new KeyAuthenticationProvider();
         if (!$keyAuthenticationProvider->hasValidKey($key)) {
             /** @var Response $response */
@@ -89,7 +89,7 @@ private function processRequest(ServerRequestInterface $request)
         $GLOBALS['TYPO3_REQUEST'] = (new ServerRequest())->withAttribute(
             'applicationType',
             SystemEnvironmentBuilder::REQUESTTYPE_BE
-        )->withAttribute('frontend.typoscript',new FrontendTypoScript(new RootNode(),[]));
+        )->withAttribute('frontend.typoscript',new FrontendTypoScript(new RootNode(),[],[],[]));
 
         if ($operation !== null && $operation !== '') {
             try {
diff --git a/Classes/Operation/HasForbiddenUsers.php b/Classes/Operation/HasForbiddenUsers.php
index 791d231..66db239 100644
--- a/Classes/Operation/HasForbiddenUsers.php
+++ b/Classes/Operation/HasForbiddenUsers.php
@@ -9,6 +9,7 @@
  * LICENSE.txt file that was distributed with this source code.
  */
 
+use Doctrine\DBAL\Exception;
 use TYPO3\CMS\Core\Database\ConnectionPool;
 use TYPO3\CMS\Core\Database\Query\QueryBuilder;
 use TYPO3\CMS\Core\SingletonInterface;
@@ -29,6 +30,7 @@ class HasForbiddenUsers implements IOperation, SingletonInterface
      *
      * @param array $parameter None
      * @return OperationResult
+     * @throws Exception
      */
     public function execute(array $parameter = []): OperationResult
     {