Make sure you have an active cellular signal.

1. Go to a place that has an active cellular signal.
2. Ensure that your phone is receiving service.
3. Check to see that your phone is not in Airplane mode.
4. Make sure the recipient’s number is entered correctly.
5. Confirm that you are sending an SMS message and not an MMS message.
6. Check to make sure you are using the correct messaging app.
7. Restart the messaging app and try again.
8. Turn your phone off and then on again.
9. Contact your phone service provider and make sure your account is in good standing.