Unicom mobile phone cards can only receive short messages suddenly.

If Unicom's mobile phone number is in a normal open state, it can receive short messages but can't send them, which is generally related to the number of the short message center. If the number of the SMS center is normal, you can call 100 10 to check whether the SMS function of this number is normal. At the same time, the following reasons are not excluded:

1. The signal is weak, there is no signal or the battery of the mobile phone is insufficient, which leads to the information not being sent normally;

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

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

4. Whether the SMS sending box is full.

In addition to the above simple troubleshooting, it still cannot be solved. You can contact the local manual customer service for processing.