diff --git a/src/Provider/Keycloak.php b/src/Provider/Keycloak.php
index 04dcf6f..d9d6a0c 100644
--- a/src/Provider/Keycloak.php
+++ b/src/Provider/Keycloak.php
@@ -201,7 +201,10 @@ protected function getScopeSeparator()
     protected function checkResponse(ResponseInterface $response, $data)
     {
         if (!empty($data['error'])) {
-            $error = $data['error'].': '.$data['error_description'];
+            $error = $data['error'];
+            if(isset($data['error_description'])){
+                $error.=': '.$data['error_description'];
+            }
             throw new IdentityProviderException($error, 0, $data);
         }
     }