I've been having trouble sending messages (SMS and iMessage) from my Mac for a week or so now. I'm not sure if it exactly correlates with my upgrading to Sierra (10.12.1) but I have a suspicion that it's related to that.
Everything used to work flawlessly but now I can't send from my Mac. New messages that I receive appear on my Mac and iPhone (it's a 6 running 10.0.2) just fine. And new messages I send from my phone also appear on my Mac just fine too.
The below screenshot shows what happens when I click the