Why does red rice mobile phone always check the format when sending text messages?

1, SMS center number is set incorrectly;

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

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

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

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

6. Blacklisted by SMS;

7. Insufficient quantity balance;

8. SMS inbox and outbox are full.