Unable to send SMS.

1, the other party set up a firewall, and your message was successfully sent, but someone else's mobile phone refused to receive it. Charge as usual, indicating that the delivery was successful, but the receipt received was a failure. 2. The other party's mobile phone is turned off, or there is no signal. The other party didn't receive the message you sent, but if the time exceeds the validity period of the message set by the other party, it will also prompt that the message was sent successfully, but the receipt received is a failure. 3. Communication problem, that is to say, it has nothing to do with the mobile phones of both parties. It may be a bad signal or a communication error.

Extended data:

1, you can check whether the information sending report of the mobile phone is on, and set this function to off.

2. If it is caused by sending a certain amount of short messages, it is generally because the short message function in the operator's office is limited. You can call the corresponding customer service to explain the situation and then cancel it, and then you can resume. (But only if the mass message is not spam)

3. You can ask people around you whether the short message is normal or not, and eliminate the influence caused by regional network failure.

4. Delete some short messages in the mobile phone to prevent the mobile phone from being sent because the memory is full. (Includes Outbox and Inbox)

5. Restart the mobile phone, and then exchange mobile phone card tests with friends.