Cannot sent SMS from Mac
Since the recent OS upgrades (macOS 10.12.4, iOS 10.3.1) sending SMS messages from mac is not working.
SMSs are received on Mac, and SMS messages sent from the phone are shown on Mac as well, but sending SMS from mac fails.
The message field in Messages shows "iMessage" for all contacts, even Android and non-existent numbers, with a message that those numbers are not registered with iMessage - see image.
"Real" iMessages are sent and received OK...
All settings checked, and logged-out and in from iCloud on all devices a couple of times.
Any ideas how to fix this?
Thanks!
MacBook Pro, macOS Sierra (10.12.4)