Change one back to InvalidStateException

osu.Server.Spectator/Hubs/Multiplayer/MultiplayerHub.cs

@@ -179,7 +179,7 @@ private async Task<ServerMultiplayerRoom> retrieveRoom(long roomId)
                     throw new InvalidOperationException("Specified match does not exist.");
 
                 if (databaseRoom.ends_at != null && databaseRoom.ends_at < DateTimeOffset.Now)
-                    throw new InvalidOperationException("Match has already ended.");
+                    throw new InvalidStateException("Match has already ended.");
 
                 if (databaseRoom.user_id != Context.GetUserId())
                     throw new InvalidOperationException("Non-host is attempting to join match before host");