Why can't I send a text message but I can receive it? I can send text messages a while ago, but I can't send them later?

Unicom's mobile phone number can receive short messages but cannot send them. You can restart or replace the phone for testing and check whether the following conditions exist:

1. SMS center number is set incorrectly;

2. No signal or low battery;

3. The system is busy during the peak period of holiday SMS sending, please try again later or avoid the peak period of sending;

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

5. The short message sending time exceeds 24 hours;

6. The mobile phone shields the short message sending function;

7. Blacklisted by SMS;

8. Insufficient quantity balance;

9. SMS inbox and sending box are full;

10. Query whether the SMS function is turned on.

If the above reasons cannot be solved, you can contact the local Unicom customer service for processing.