Several users have reported that iMessage has stopped working, meaning they are unable to send or receive messages after they upgraded their devices (iPad, iPhone or iPod) to iOS 6. Users are also reporting “Not Delivered!” errors in Messages. Here is how to troubleshoot your issue, please try each step until you fix your problem:
- Make sure that Messages is tuned on (Settings > Messages > iMessage).
- Tap Settings > Messages and turn iMessage off and back on again.
- Make sure that your Apple ID or phone number is listed in Settings > Messages > Send & Receive.
- Restart your device by pressing and holding the Sleep/Wake button, then toggle the “slide to power off” slide. To turn the device back on, press and hold the Sleep/Wake button until the Apple logo appears.
- If nothing above works, try changing your DNS settings as described here.
Note: Your iPhone/iPad or iPod must have a valid cellular or Wi-Fi connection.