I was able to send MMS normally before, but suddenly I found that I couldn't send it. I kept showing all the settings in the process of sending, and I checked that there was no problem.

I suggest you check the following steps to find out whether

1 SMS sending and receiving is normal or whether the number of SMS center is correct. (No need to set SMS center number for telecom version)

2 Turn on the option of always receiving MMS. ("System Settings" > > "all settings" > > "mobile network" > > "Always accept MMS")

3 Ask the operator whether to open the mobile Internet service. MMS can only be sent successfully if it has the function of "surfing the Internet by mobile phone", but there will be no traffic charge, and operators will charge according to the number of messages.

4 whether the selected attachment is too large, operators generally have strict size restrictions on the pictures sent by MMS, please consult the operators for details.

5 it is recommended that you change the sim card of different operators and try to send it.

6 it is recommended that you back up the data, then empty all the data, upgrade to the latest version of miui development version, and then try sending again.

7 If the problem has not been solved, please go to the maintenance point near you for maintenance inspection /service/poststation

A more detailed description of the problem will help netizens understand the trouble you have encountered and help you solve the problem more accurately. Thank you for supporting Xiaomi mobile phone!