Solutions:
1. Check if the SMS center number is correct. Different operators in different regions have different SMS center numbers, and add oneself after consulting local operators.
2. If there is no option to modify the SMS center number in the mobile phone, then enter * # * # 4636 # * # *from the dial-up interface. Find the corresponding SIM card (mobile phone information 1 or 2), tap the update after SMSC to see if it can be got automatically. If that’s successful, test if the phone can send text messages (see image for details).
3. If sending text messages fails, take off the mobile phone card, insert it in another mobile phones to set up the SMS center number, and insert the SIM card back into the mobile phone again.
4. If there is power saving, optimization, assistant, app that would force to end tasks and other optimization software, it is suggested to shut down or uninstall them.
5. If the issue persists, it is suggested to download upgrade packages from Xiaomi community and try update again.
