My Unicom card doesn't know how to send short messages but it can receive them. What happened?

The possible reasons are: 1, the number is in arrears, the state is down, and the SMS cannot be sent; It is recommended to pay attention after payment. 2. Check whether the number of SMS center is set correctly. Incorrect SMS center number will also affect the sending of SMS. 3. Due to the frequency and content of sending short messages, the system will intercept the sent keywords and other information, and temporarily close the short message function; This situation needs to be confirmed by connecting the local customer service hotline 100 10. Tip: SMS center numbers vary from region to region. Please contact your customer service hotline for details. For example, the number of the short message center in Beijing is+861301kloc-0/12500. Half-year traffic is not cleared across months and is valid for half a year. Click /sAAGm to enjoy a 20% discount!