diff --git a/Classes/Processor/ImgProxyProcessor.php b/Classes/Processor/ImgProxyProcessor.php
index f55acd6..275e145 100644
--- a/Classes/Processor/ImgProxyProcessor.php
+++ b/Classes/Processor/ImgProxyProcessor.php
@@ -82,8 +82,8 @@ public function processTask(TaskInterface $task)
             );
             $urlBuilder->setResizeType('force');
         } elseif (
-            str_ends_with($processingConfiguration['width'], 'c') ||
-            str_ends_with($processingConfiguration['height'], 'c')
+            str_ends_with($processingConfiguration['width'] ?? '', 'c') ||
+            str_ends_with($processingConfiguration['height'] ?? '', 'c')
         ) {
             $urlBuilder->setResizeType('fill');
         }