Player keeps getting disconnected with the same error (see first picture)

I'm running a modded Forge 1.20.1 server and a player recently has been unable to join, getting this error whenever he tries. It started after he got kicked from the game with the error in the second picture. I have attached a log from around the time he first got kicked:
https://mclo.gs/nHoobqV

Does anyone know what may be causing this issue and/or how to fix it?