I just got an error that I've never seen before from my minecraft server

So my server was running great until a few days ago when I randomly got this error: io.netty.channel.AbstractChannel$Annotat… Connection refused: no further information:
Note: the server is for Minecraft 1.12.1, which is the version that I'm currently on. I'm running my server on a raspberry pi in my living room. We noticed the "permissions.yml" file was empty so we redid it and it's having the same error. It runs perfectly until someone joins, if somebody joins, it crashes. We have tried restarting the server numerous times but it never worked.

Added (1). so i noticed the error message got cut off, here: io.netty.channel.AbstractChannel&Annotat… Connection refused: no further information:

Added (2). lol
io.netty.channel.AbstractChannel
$AnnotatedConnectException: Connection refused: no further information

Wow

Maybe just get off of minecraft and go outside.