diff --git a/src/Configuration.php b/src/Configuration.php
index 15d15e2f..42a56638 100644
--- a/src/Configuration.php
+++ b/src/Configuration.php
@@ -423,7 +423,7 @@ public function getQueryColumnConfig($entityName)
      */
     public function getMutationColumnConfig($entityName)
     {
-        return $this->getMutationEntityConfig($entityName)['columnConfig'];
+        return $this->getMutationEntityConfig($entityName)['columnConfig'] ?? [];
     }
 
     /**
diff --git a/src/GraphQL/Mutation/MutationType.php b/src/GraphQL/Mutation/MutationType.php
index e6032a71..edfad65a 100644
--- a/src/GraphQL/Mutation/MutationType.php
+++ b/src/GraphQL/Mutation/MutationType.php
@@ -779,7 +779,7 @@ public function generateInputFieldsAndProcessors(&$inputFields, &$processors, $c
             /** @var Configuration $configurationItem */
             $configurationItem = $context['configuration'];
 
-            $columns = $configurationItem->getMutationColumnConfig($entity)['columns'];
+            $columns = $configurationItem->getMutationColumnConfig($entity)['columns'] ?? [];
 
             if ($columns) {
                 $fieldHelper = $this->getGraphQlService()->getObjectFieldHelper();