Unknown letter display failed to send.

If you use a vivo phone, you can view the following information:

1. Some short messages could not be sent.

1. Confirm whether the phone bill balance is sufficient.

Please confirm whether the phone bill of the mobile phone card is sufficient. If the phone bill is not enough, sending SMS will fail.

2. If the short message contains sensitive words, the other party cannot receive it after sending it.

Please use the test statement to send a short message to confirm whether the other party can receive it normally, such as sending: hello, thank you, etc. If the other party can receive it normally, it means that the text message sent before may contain sensitive words.

3. Confirm whether the "fixed dialing" service is enabled.

When fixed dialing is turned on, you can only send information to the contacts in the fixed dialing list, but not to other numbers. If you want to continue sending SMS, please cancel the fixed dialing service. Enter settings-(application and permissions)-system application settings-telephone-corresponding SIM card-fixed dialing, and close fixed dialing (you need to input PIN2 code and consult the operator when closing).

4. Unable to send short messages to some short numbers.

Please go to the information App-3 o'clock in the upper right corner-Settings-More Settings-Send payment information. It is recommended to set it to every query.

Second, all text messages can't be sent.

1. Confirm whether the phone bill balance is sufficient.

Please confirm whether the phone bill of the mobile phone card is sufficient. If the phone bill is not enough, sending SMS will fail.

2. Switch flight modes

You can try to switch flight modes, re-trigger the network and try again.

3. Check whether to use a third-party SMS APP.

Third-party SMS apps may have compatibility reasons, so it is recommended to use the SMS app that comes with the system. Go to Settings-Applications and Permissions/More Settings-Permissions Management-Permissions-Default Application Settings-Information and set it to Information.