Why can't some short messages be sent out?

If you use Unicom's mobile phone card, if there is a problem that the mobile phone can't send short messages, you can troubleshoot it by the following methods:

1. SMS center number is not set correctly. Please re-enter the correct SMS center number.

2. There is no signal or the battery of the mobile phone is insufficient;

3. The system is busy during the peak period of holiday SMS sending. It is suggested that you try again later or avoid the peak period of sending.

4. The sending format/number is incorrect;

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 outbox are full.

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