diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index c09f2dec4..12e84a2b7 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -67,7 +67,7 @@ class ThumbnailResource(Resource):
                 yield self._respond_local_thumbnail(
                     request, media_id, width, height, method, m_type
                 )
-            self.media_repo.mark_recently_accessed(server_name, media_id)
+            self.media_repo.mark_recently_accessed(None, media_id)
         else:
             if self.dynamic_thumbnails:
                 yield self._select_or_generate_remote_thumbnail(
@@ -79,7 +79,7 @@ class ThumbnailResource(Resource):
                     request, server_name, media_id,
                     width, height, method, m_type
                 )
-            self.media_repo.mark_recently_accessed(None, media_id)
+            self.media_repo.mark_recently_accessed(server_name, media_id)
 
     @defer.inlineCallbacks
     def _respond_local_thumbnail(self, request, media_id, width, height,