1 files changed, 5 insertions, 1 deletions
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 30b4cb23df..520c52e013 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -1679,7 +1679,11 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         ]
 
         if len(remote_room_hosts) == 0:
-            raise SynapseError(404, "No known servers")
+            raise SynapseError(
+                404,
+                "Can't join remote room because no servers "
+                "that are in the room have been provided.",
+            )
 
         check_complexity = self.hs.config.server.limit_remote_rooms.enabled
         if (