Xiaomi 1s can't send short messages after changing SIM cards. Yesterday was a mobile m-zone and today it has been changed to Unicom. They're all 2g. What should we do?

1. Please put your mobile phone card in another mobile phone to see if you can send and receive short messages.

2. If you can't receive the short message, please contact the network operator to see if it's the sim card.

3. If you can send and receive short messages, I suggest you plug the card back into your mobile phone and send yourself a short message to see if you can receive it.

Please enter the SMS center and contact your mobile operator to check your SMS center number.

If the number is correct, please temporarily uninstall your system security software.

6. If it still can't be solved, please back up the data, enter Restore to clear the cache, user data and all data, and don't restore the system settings after entering the system.

I hope the above reply is helpful to you.