Apple 7 can't send text messages. What happened?

First, the mobile phone has security software settings to intercept sending short messages. Find and modify such software, or try another mobile phone.

Second, eliminate the problem of mobile phone, indicating that your mobile phone sends too many short messages, which is judged by the system as sending spam messages and is stopped to send. Call customer service or bring your mobile phone card to the business hall. After the demonstration, the customer service will contact the background data to find out and solve it.