What is the reason why I can't send text messages after vivo update?

What do you prompt when sending? It may be because your network environment is not good, so I suggest you try the following methods to solve it:

1, try another area or time period with good signal;

2. Enter Information-Left Menu Button-Settings-Restore Default Settings;

3. Please confirm whether the SIM card is turned off (go to Settings-Mobile Network to check);

4. Check whether the phone bill of the SIM card is enough or try to replace the SIM card;

5. Enter information-left menu button-Settings-SMS center number-Check whether the SMS center number is correct (local SMS center number can be searched online);

6. Enter the phone settings-More settings-Restore factory settings-Restore all settings (without deleting any data of the phone).