Why does my mobile phone show that the SMS was sent successfully, but others didn't receive it?

The reasons why the SMS was sent successfully but not received by the other party are as follows:

1. The receiver's memory is full, so just delete the redundant messages.

2. The receiver signal is poor, so it is recommended to send it to a place with good signal.

3. Congestion, packet loss or interconnection obstacles affect the processing of short message center.

4. SMS function is not enabled.