Unknown login error [9]

hello, anyone have this Problem? i have it every time i want to relog with Manger after Dc
i use v.1.8.3

Use the client to login to whatever server you’re playing on.

the bot client ? same Problem ^^ and i dont log in clientless because the Server dont accept

Server?

yes private Server. v.188 if you want i can send u the link if you want to check it?

Which server specifically?

if it allowed to send links to other Servers?