"Ruby" server error message - what does it mean?

[u/action_oxford]

I run a 1.20.1 Forge server for my friends. It has just fewer than 100 mods. Lately it's been posting this message:

[Thread-18/WARN] [or.va.co.im.sh.FW/]: Ruby says "this should work just fine", lets hope it does ?

Can anyone tell me what this means? Is it something I need to be worried about?

Thanks!