If you are having trouble receiving or sending messages with either iOS 6 or 7 try these steps out.
Make sure “Do Not Disturb” is turned off.
Two ways to get to Do Not Disturb. Easiest method is swipe up from the bottom of the screen to pull up the shortcut tray. Locate the Moon looking symbol near the top of the tray. That is your Do Not Disturb toggle icon. Make sure it is not lit up (meaning it is off). If lit up, simple touch to deactivate.
The next method is a little bit longer but will get the job done and will let you see a few more options. First go to the Settings App. Scroll down not too far and you will see a Do Not Disturb tab. Select it and on the righthand side you will have the options to toggle the feature off.
The second way to troubleshoot is to Reset Network Settings. This can actually speed up your data as well. Go to the Settings App > General > Reset > Reset Network Settings. This will reboot your phone and should at least fix slow speed and perhaps sending/receiving messages.
Another option is to make sure you have a ringtone set to iMessage, not a silent ringtone or make sure you don’t have certain contacts set to silent or Do Not Disturb.
If these methods do not work, Apple is supposed to release a bug fix updates soon. If the update does not work, call customer service and you should be able to get a replacement phone.
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