diff --git a/get_peertube_videos/get_peertube_videos.py b/get_peertube_videos/get_peertube_videos.py
index 23984b3..4d72ad9 100644
--- a/get_peertube_videos/get_peertube_videos.py
+++ b/get_peertube_videos/get_peertube_videos.py
@@ -86,6 +86,11 @@ class GetPeertubeVideos:
                 len(attachments)
             )
             for attachment in attachments:
+                if size_field not in attachment:
+                    self._log.error(
+                        "Attachment without file size. %s",
+                        attachment
+                    )
                 if attachment[size_field] > selected[size_field]:
                     selected = attachment
             if 'url' not in selected: