well, i got this problem so long ago, i do almost all of these thing on the "fix thread" and nothing :/

i only play on the matchmaking :/

So matchmaking works but multiplayer rooms don't?
Sounds like a firewall issue. Also which version of the game are you using?

i'm using 5.12, i try disabling the firewall and doesn't work :,v

I'd suggest getting Steam version if possible. It will be 5.14 + steam version tends to be more stable.

Is it a specific server? Or all, supposedly some servers crash reserve a slot until issue is fixed

Have you changed your password, and have not relogged on the game with the new password?
That would be my guess.

that's not the case, since matchmaking works

I would have no clue, if so, I would go with what smaguris said, try the steam version if you haven't already. It is in some cases better.