Why doesn't iphone6 always send text messages automatically?

It may be that there is an IOS SMS virus in the mobile phone, which is characterized by sending text messages by itself. It is recommended to restore the mobile phone to the factory settings.

Steps to restore the factory settings of Apple's mobile phone:

Enter the setting interface, and click [General] in the setting interface;

After entering the general interface, click Restore;

After entering the recovery page, click the option to restore all settings.