My NOTE4 (dual-SIM public version) uses two mobile cards. I always have problems sending text messages. I don’t know what to do?

Based on your description, it is recommended that you try the following methods:

1. Restart your phone to see if it is a signal problem.

2. Settings-Application Manager-Sliding Screen Options (All)-Find Information-Click to enter, clear data and try again

3. Try changing other SIM cards

4. Check whether the security guard or third-party SMS software is installed on the phone and test after uninstalling it

5. Back up mobile phone data (phone book, text messages, multimedia files, etc.) and restore Factory settings

If the above method still does not work, please send the device to a Samsung service center, and an engineer will check the machine and handle it.

For the specific location of Samsung Service Center, please click the following link:

.samsung.com/support/ServiceLocations.asp