Issue while joining worlds.

[CDM]

My friend has been having issues with joining my new modded minecraft server but this error has been coming up over and over, even if he starts a singleplayer world:  minecraft internal exception: java.lang.class cast exception: java.lang.boolean cannot be cast to java.util.list

We both have the same mods and the same version of everything but we dont even know what the error means and how to fix it. It works for me but it doesnt work for him. Please help cuz we have been suffering with this for hours. If you need any more info contact me and Ill ask him for whatever you need or even the mod list (we have 66 mods in total) We are on the newest verion of forge on 1.16.5. We have updated Java, tried add more memory to the installation and nothing worked so far. 

Well thank you very much in advance.

Edited May 1, 2022 by CDM

[Luis_ST]

post debug log from server and client

[CDM]

The server log:   https://paste.shockbyte.com/ikafiyaguzomerigunah

(I cant add the client log right now but I will as soon as he is online)