Samsung note4 can receive short messages, but can't send them. Why?

According to your description, I suggest you try the following methods:

I suggest you go to Settings-Applications-All-SMS-Clear Data.

Restart the phone to see if there is a signal problem.

Check whether the number of the information center is correct: Information-Menu button in the lower left corner-Settings-Information Center. Only GSM mobile phones can modify the information center number, CDMA mobile phones do not support it. The number of centers in different operators and regions is different. Please contact the network operator for confirmation. The number of the information center must be preceded by "+".

Try to replace another sim card, or wipe the contact point between the mobile phone card and the mobile phone (whether the SIM card is in poor contact).

It is recommended that you try a firmware upgrade. (Settings-About Equipment-System Update)

If you still can't send and receive SMS through the above methods, please bring the purchase invoice, maintenance card and machine to Samsung Service Center, and the engineer will check and handle the machine. Please click the following link to find out the specific location of Samsung Service Center:.