Apple iMessage
A fix is available for iMessage activation issues after TaiG iOS 8.3 jailbreak Apple

Several reasons have been attributed for iMessage's activation issues. Changing SIM cards, iPhones or, even phone numbers can lead to iMessage behaving oddly.

If you experiencing iMessage activation issues after jailbreaking your iOS 8.1.3-iOS 8.3 device with the TaiG untether tool, there is a fix available, thanks to a Redditor named iPodZombie. The fix seems to have helped those facing the activation problem.

However, the issue need not necessarily have stemmed due to a jailbreak error, and could as well be related to iMessage itself as such issues have also been reported on non-jailbroken devices. Perform the following steps to fix the offending iMessage activation.

  • Enter Safe Mode. This can be done using any method such as using an Activator action. You may also use tweaks like Power Tap to enter Safe Mode
  • In Safe Mode, go to Settings>> Messages, and then toggle iMessage off and turn it on again. A text should appear saying Waiting for activation as it usually happens during activation
  • Scroll down and tap Send & Receive. Your phone number should be selected. If you want to use your Apple ID for iMessage, go ahead and sign in
  • Return to the home screen and exit safe mode by tapping the Exit Safe Mode in the status bar and click Restart

Your iMessage should now function normally.

Via Redmond Pie