Why can't my mobile phone send a message at once? It's a Unicom card. It's checked normal.

The reasons why mobile phones can't send short messages are as follows:

1. SMS service is not enabled on the mobile phone. You can contact 100 10 customer service or go to the local business hall to activate this function.

2. If the SMS center number is not set or set incorrectly, just reset it;

3. The signal is weak, there is no signal or the battery of the mobile phone is insufficient, resulting in the information not being sent normally;

4. Because the system is busy, especially during the peak period of sending short messages on holidays, it is suggested that you try again later or avoid the peak period of sending short messages;

5. The sending format is incorrect. If you send a short message to PHS users, you need to add the area code before the number;

6. SMS sending and retention is valid for 24 hours;

7. Whether the SMS inbox and sending box are full;

8. I suggest you restart your mobile phone or change it for a test.

In addition to the above simple troubleshooting, it still cannot solve the problem. You can go to the local business hall to test the sim card. If the sim card is invalid, it is recommended to replace it.