Before reporting:

Please use the search function to make sure an issue hasn't been reported already. This avoids duplicates.
Also, please give this issue a descriptive name that contains the game version in the title, eg.: "[1.12] Capacitor Interaction Crash"

Description of the issue:

I run the server but everytime someone tries to join it fails and it keeps saying Internal Exeption: java.io.IOException: An existing connection was forcibly closed by the remote host

Crashlog:

https://pastebin.com/zTa25TnH

Versions & Modlist

ImmersiveEngineering-1.16.5-5.0.7-143.jar
on the Crazy Craft Updated 0.7.8 server pack

That crashlog is from mod loading, it doesn't tell us anything about issues on joining.

Gonna close this, since issue and log are seemingly unconnected.