diff --git a/lib/classes/JsonApi/Errors/ErrorHandler.php b/lib/classes/JsonApi/Errors/ErrorHandler.php
index 93549b50a169c007021cb554e7ef5749c1ead8e9..04224debfaf4c51c5792b8ad4a722de914dbeca5 100644
--- a/lib/classes/JsonApi/Errors/ErrorHandler.php
+++ b/lib/classes/JsonApi/Errors/ErrorHandler.php
@@ -35,6 +35,7 @@ class ErrorHandler
         }
 
         $response = $this->app->getResponseFactory()->createResponse();
+        $response = $response->withHeader('Content-Type', 'application/json');
         $response->getBody()->write($this->determinePayload($exception, $displayErrorDetails));
 
         $code = $this->determineStatusCode($exception, $request->getMethod());