Why do I keep getting message Not Delivered on my text messages
Why do I keep getting message Not Delivered on my text messages
iPhone 4S, where is the operating system
Because they have not been delivered due to some reason!
Check that you have connectivity to your cellular network (if using SMS), and that you have a data connection as well (if using iMessage).
In addition, call the intended recipient and ask that they check the same.
You may also want to power off and then back on your phone.
Then test some messages.