iMessage on Mac no longer able to send/receive from my number

[ChrisD.]

It used to work, but all of a sudden Messages stopped working. I had to re-sign it into my ID, but I can't select a phone number to receive/send from and to. Any ideas? I've tried signing out, in, restarting, restarting my phone, no change.

 

[ChrisD.]

Tried, no change.

 

[ChrisD.]

Yes, the iPad is, well in terms of iCloud it is, but it's never been used for messages. Except I think my GF user her account on it to sign into iMessage.