Every time I try to login to my 1.20.2 Paper server with Wurst I get this error message. It only occurs when using Wurst mod- other mods work fine but as soon as I try to use Wurst I get this error msg whenever I try to send a msg or a command in chat.

How can I fix this? Oddly I can chat on Hypixel but cannot chat on my 1.20.2 Paper server, though Hypixel is not 1.20.2 and uses ViaVersion to allow other versions to join.

I do have access to server files so if needed I can change something- but I'd like to avoid doing so as I figure there must be a reason for the settings to be the way they are.

Error msg in chat:

Feedback would be greatly appreciated, thank you!

Edit:
After reviewing:
https://bugs.mojang.com/browse/MC-252942
I suspect it occurs with servers 1.19+ and when using specific client-side mods that cause this problem. Hence why Hypixel worked because it runs on 1.7 or 1.8 and why my 1.20.2 server did not work with Wurst but works fine with vanilla or other mods.

Still looking for a fix.