What is the reason why Unicom's mobile phone can't send short messages?

Dear, the reasons why you can't send text messages are as follows:

1, the phone bill is insufficient, please pay and try again.

2. The center number is set incorrectly. Please check and correct it. The center number is different in different regions (for example, Jinan's is+8613010171500). Please contact Unicom customer service for details.

3. The SMS function of the mobile phone card is abnormal. Please consult customer service to check whether the SMS function is normal.