Text wall when trying to join a server

If this applies to just one server, I think it's just a kick message that wasn't correctly formatted (server's fault) and that the "Back to Server List" button appears below the screen (meaning you can't click it) but you could press it by pressing Tab and Enter.

Are you running a vanilla instance of the game?

Please give steps to reproduce this issue

I had the exact same issue just now. Was afk with game in the background and when I checked after ~1h i had this wall of text and on every subsequent try to join any server. Vanilla launcher, servers had plugins. My internet works fine for anything else, but it does say "Service unavailable" somewhere in the error message. The servers themselves are still up and running.

I just tried it again (for the 10th time) and finally could join the server. Still don't know what caused it.

you can click Back to server list by resizing window to regular but flip 90 degrees. I got this error too