Hmm, not sure how Primal works but perhaps it can’t connect to your private relay. It’s possible they use their own server to connect to relays (instead of you connecting directly) but again I don’t know much about Primal. 

 Added my NIP-05 to Primal and it seems to sync (I’m currently on the same network as the relay) 

 Nm, no workie. Guess I’ll hang out in Damus 

 Yeah if the relay is only accessible through your private network then that could be why Primal has trouble accessing it