What is the reason why the sim card of Xiaomi 4 mobile phone can't activate SMS?

This usually happens when Xiaomi's network short message function is turned on, that is, to turn on this function, the SIM card is needed to send an activation short message to Xiaomi's server. If it is not set or there is a problem with the server, the activation will fail. The solution is as follows:

1, you can enter the SMS interface, click the menu button, click to enter the SMS setting interface, and then click MIUI free network SMS to start this function.

2. If it still can't be solved, you can try to change a SIM card, then restart your phone and try again.

3. If the above methods can't be solved, it is recommended to contact Xiaomi directly after sales to conduct a comprehensive inspection and maintenance of the mobile phone.