Issue:

I'm currently running forge 31.2.47 on a dedicated server, but whenever a client tries to join, the first image with an error shows up and the player gets instantly disconnected from the server. It seems that removing around 10-ish larger content mods seems to solve the problem, but removing anything less than that causes the issue to return again. Removing just one mod, Forbidden and Arcanus, seems to change the number on the error, which you can see in the second image. Just playing without the removed mods is not an option for me, which is why I'm reporting this problem. In addition to that, it seems like no particular mod is the problem, as changing the amount of mods only seems to change the number that shows up in the error, and also the fact that it doesn't matter which group of mods I remove in order to solve the problem. This might mean that it's a problem on forge's side.

Logs and Mod Info:

Here are my latest logs from both the server and client, as well as the modlist and my system info: 

Modlist: https://gist.github.com/msidd02/f00cc7c91c0ad9a380fec28636261bbf

Client: https://gist.github.com/msidd02/dfa9f538187bf15a3458e9a0a3067154

Server: https://gist.github.com/msidd02/6ef33d1be500f0cd4be33b993f0b0648

Server Debug: https://gist.github.com/msidd02/e7202fc292aface5cd84507a877e003d

No crashes occurred anytime during this, only disconnects. 

Reproducing the Issue:

To reproduce the issue, you'd mostly like have to try setting up both a forge dedicated server and client with the same or similar modlist and forge version, and then try to join the server from the client via localhost. The only similar problems I could find online were about a problem with Hypixel 1.15 or 1.16 servers, which is why I ended up having to ask here. 

Edited December 13, 20204 yr by cats342

The Git seems to be for 1.16, so I'm assuming the issue won't be fixed for 1.15? Also, does that mean the only solution then is to add less mods?

I see. I was able to find this 1.12 forge mod that seems to solve the issue, but nothing like that exists so far for 1.15/1.16 yet from the looks of it. Thank you for the help and sorry for bringing up a problem you guys already knew about.