How do I troubleshoot not being able to send a text message when I can receive them?

To troubleshoot text messaging issues from your T-Mobile phone, perform the following steps: 1. Turn your T-Mobile device off and back on again.
2. Select someone in your address book who is a T-Mobile customer.
3. In the body of the message, enter *NOTIF.
4. Send the text message. Verify that you have included a 1 along with the area code.
5. If the delivery is successful, the recipient will receive a blank message. You should then be able to send text messages to other contacts.
6. If you are still unable to send a text message, try placing your SIM in another device and send a text message again.
7. If the recipient did not receive the text message, please contact us.