diff --git a/core/modules/media/src/Plugin/media/Source/OEmbed.php b/core/modules/media/src/Plugin/media/Source/OEmbed.php
index e789b702d0..20ce267e2c 100644
--- a/core/modules/media/src/Plugin/media/Source/OEmbed.php
+++ b/core/modules/media/src/Plugin/media/Source/OEmbed.php
@@ -384,6 +384,7 @@ protected function getLocalThumbnailUri(Resource $resource) {
     if (!$remote_thumbnail_url) {
       return NULL;
     }
+    $remote_thumbnail_url = $remote_thumbnail_url->toString();
 
     // Remove the query string, since we do not want to include it in the local
     // thumbnail URI.