Unable to connect, please restart your client(Empty Auth from Discovery)

Hello!! I have a serious problem with playing multiplayer game with my friends in my own world.
They are unable to join my world. I can not join their world either.
I see the "Unable to connect, please restart your client(Empty Auth from Discovery)" screen after failing joining into friends' world. I can join official servers like Hive though.....

In my case, the problem has been appearing since about 1 month ago. I had been struggling with "Unable to connect, please restart your client(Expired Auth from Discovery)" bug before this bug appears. PLEASE FIX THIS BUG AND HELP ME!!!!!!!!