FaceTime Activation (An error occurred during activation try again )

If you can't sign in to your iMessage account or FaceTime on your Mac

If you get an error when trying to activate iMessage or FaceTime - Apple Support

Whether or not you'll be able to get FaceTime depends on where it came from and where you are:

iPhones originating from Israel or outside the Middle East(except Pakistan) will have FaceTime worldwide. If it's missing on these, check the device’s restrictions, search for it, or redownload it from the iTunes App Store.

iPhones which have AH or HB just before the slash in their model numbers work the same as those in #1. To check this, choose Settings, General, and About.

iPhones which have AB, AE, or UR just before the slash in their model numbers will only have FaceTime in Egypt, Qatar, Oman, Jordan, Lebanon, Bahrain, or Kuwait; it's tied to SIM cards from those countries. While Saudi Arabia and the United Arab Emirates lifted the ban on it, the SIM cards there won't enable it at this time.

[Originally posted by user Niel.]