Xiaomi 9 can receive short messages but can't send them.

1. Please insert your mobile phone card into other mobile phones to see if you can send and receive short messages.

If you can send and receive short messages, I suggest you re-insert the card 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.

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

6. If you still can't recover, please go to the repair point near you for testing.

Address and telephone enquiry: /service/poststation At the same time, nine millet homes in Beijing, Shanghai, Nanjing, Wuhan, Chengdu, Hangzhou, Xi, Shenzhen and Guangzhou also have maintenance capabilities. Xiaomi House works from Tuesday to Sunday.

I hope the above reply can help you.