Weird issue accessing HAS via wireguard

i set up HAS in a way i access it via https:// public domain …:port, all works fine. When I connect my pc via wireguard to my local network i am not able to access HAS, getting error as

any idea what kind of error it could be/ or how to debug it?

okay my wireguard has DNS set to
when i set it to the IP of my router, it all works fine.