Activation

You should check this article: If you can't activate your iPhone - Apple Support. If you can't activate your iPhone or iPad (Wi-Fi + Cellular) - Apple Support

Some have reported that temporarily removing the sim allows activation to complete.

Otherwise, 5 possible causes for that error message:

1] Activation server is actually down. Very rare occurrence, and of short duration when it

does happen. Solution - try again.

2] Your firewall and/or antivirus software are preventing the necessary connection. Solution -

temporarily disable your firewall and/or antivirus software until the activation completes.

3] computer being used for activation has been used to jailbreak an iOS device in the past.

Solution - use a different computer.

4] iPhone has been jailbroken. Your favorite search engine may provide some direction, but jailbreaks often prevent

activations/updates from succeeding. Per Terms of Use for this forum, discussion of jailbroken iPads is

prohibited.

5] your region and/or timezone settings are inconsistent with your actual location. Solution - set region and/or timezone correctly.

Anecdotes in the forum say that Apple has changed the way the activation server is contacted and that older iPhones on obsolete versions of iOS can no longer reach the server. Some have recommended using a PC or Mac

activate the iPhone in such cases.

Your device needs to have communications to the internet - either via mobile data or WiFi - to be able to reach Apple’s activation servers.