Why does Samsung mobile phone S4 always show that it can't send information at present, and then send it when there is a signal?

If the mobile phone can't send short messages, it is suggested that:

1. Check whether the phone bill is sufficient.

2. Check whether the information center number is entered correctly: information-menu key-settings-SMS settings-information center-set the information center number (please contact the local network operator for the information center number, and the telecom card is not set with the information center number).

3. Try to replace another SIM card.

4. Check whether the machine has a firmware/system update push notification. If so, please upgrade the mobile phone to the latest version.

5. If it is invalid, please back up data (contacts, multimedia files, etc.). ) and restore the machine to factory settings. (Note: Please back up the relevant materials before updating the version or restoring the factory, so as not to affect the use. )