You write to your DM relay list basically localhost and some port. My client reads your DM list and tries to send the DM to localhost. But that will never arrive. Similar situation when people use paid or auth relays as their inbox relays. Because others will write there but maybe don't have write permissions on the relay.

Makes perfect sense I remember why I added it there in the first place; I was playing around with the idea of sharing the same local relay, on the same local network between two different devices It did work, but always better off to just walk to the other room and actually speak to the person