Cannot login into iMessage

For me the issue was that iMessage was not "registered" or "verified" on my iMac. I called apple care and they said that they do not have a conclusive reason why this happens, but some applications on a Mac, due to OS updates or upgrades, or due to validation of hardware since purchase, need to be approved for use on a specific hardware / operating system configuration - effectively it's a license issue. When you provide the code in the error message to Apple support, they use the Apple ID to you are signing in with and the code to verify or register that application for use on that Mac. They said this issue may or may not occur on some Macs and they don't know specifically why. They also said that using a specific Apple ID to get this verification or registration of the application completed does not mean that the application is locked to that Apple ID, once this process is done you should be able to use any Apple ID as the application has been registered to the Mac not the Apple ID.

Hi,

This pop error messages with the Code number on it only appears on computers updated to OS X 10.8.2 which is when Messages is Updated to version 7.0.1 which is when the app starts to use the Serial Number as part of the Device Specific Login.

The Pop up does not appear if the Serial Number is missing (which was more frequent prior to Messages needing the Serial Number).

As you say the issue continues right through to Sierra but does seem more linked to Updates and Upgrades from Yosemite onwards but the Code number error pop up does not appear in those versions.

If people are trying to resolve this without the pop up and code they have to contact Apple Support and say they have an Apple ID issue and work their way up the support chain until someone can check the server and see their ID is blocked and get it reset. (this can involve lots of data gathering and "tests" as Apple try to get a handle on this.

8:48 pm Wednesday; November 23, 2016

None of these steps worked for me. This happened after I authorized two factor verification. But when it asks me for my apple id and password i get no si digit number on a device to add

I am facing the same issue after the last update. I'm using 2016 MacBook Pro and my os version is 10.12.4.

Please advise a way to solve this.

Thanks,

Fahad

If you find the answer, please let me know