So since about 3 hours ago I got spammed with error messages
I downloaded the latest version, no change

seems like umod didn't update properly on my server

If you don't want get errors in your Discord then don't enable it?
This is not a place to report errors like this. Plugin works exactly as expected and sends messages about errors on your server. This error is not related to plugin nor uMod.

P.S. Next time you better copy-paste error text instead of screenshot. Also try to google it before posting.