I have an iPhone (iOS 10) and a macbook (macOS 10).
My SMS/iMessages used to be in sync between my computer and my iPhone.
At some point, not sure when, they stopped syncing.
- Both devices are connected to my Apple ID.
- Handoff is enabled.
- iMessage is enabled.
Best Answer
First of all, I've had a less than prefect experience with messages being delivered to both Mac and iPhone which I largely attribute to non-Apple devices.
To your problem, have you tried un-ticking phone numbers/email accounts and signing out on both devices? Quit app then re-lauching and signing back in?