diff -u b/src/Context/ContextUploader.php b/src/Context/ContextUploader.php
--- b/src/Context/ContextUploader.php
+++ b/src/Context/ContextUploader.php
@@ -247,6 +247,10 @@
           if (!in_array($item['resourceId'], $cached_data)) {
             $update_cache = TRUE;
             $cached_data[] = $item['resourceId'];
+
+            $this->logger->warning("File @file can not be downloaded.", [
+              '@file' => $item['url'],
+            ]);
           }
         }
       }