I failed to sign in with my Apple ID to activate iMessage on Mac OS 10.12.3. But ironically, I could sign in at my iPhone and iPad. I could also login to my iCloud using browser. This is only after I updating OS yesterday to the latest version.
MacBook Pro (13-inch Early 2011), macOS Sierra (10.12.3), no comment.
OMG I finally fix it!!!
1. You should turn off iMessage and FaceTime on your mac
2. Turn off your mac
3. PRAM reset! - hit the power button and immediately hit P + R + cmd + opt at the same time until when you hear 'second beep' sound. When you hit the P R cmd opt key pad at the same time, it will re-booting your mac.
4. Log in your iMessage and Face time!, you'll get notification message on your iPhone or ipad !
Hope this works for you guys!
This exact same thing happened to me. Worked fine until the latest system update.
I have same happened too 😟
This is the correct answer! I actually called Apple support and got the same solution. They should have posted on their website.
failed to sign in with my Apple ID to activate iMessage on Mac OS 10.12.3
