Exception connecting: IOException: Connecting reset by peer @ sun.nio.ch.FileDispatcherImpl: -2?

When I try to join my Minecraft server this message comes up.

exception connecting: IOException: Connecting reset by peer @ sun.nio.ch.FileDispatcherImpl: -2

What do I have to do?

Info:
1.15.2
Cloudnet V3
I use Putty and FileZilla
Bungeecord
ka what could be so important.

I switched to cloudnet 2 again 😂

The V3 has sooo many bugs

Yes, unfortunately I'm already ready.
I've already set everything up just sometimes the server is simply stopped and then the lobby server starts and stops and that in an infinite loop and the console is then spammed so hard that you can hardly concentrate and read the errors…
Cloudnet V3 support is already ignoring me xD I asked so many questions xDD