Connection Lost Internal Exception: java.io.IOException: An existing connection was forcibly closed by the remote host

Three of my friends keep getting kicked from my Realm. Two days no issues, but today out of nowhere they get the mentioned error.

We have tried every solution we have found online.  Help!

They all have the same ISP - so Im sure that might have something to do with this. But is there anything that can be done?

Thank You!