Fixing SMS Sending Issue on Android 6 helps you overcome the problem of being unable to send messages to the service center.
To fix the SMS sending issue on Android 6, follow these steps:
Step 1. Select settings.

Step 2. Choose applications.

Step 3. Select more options.

Step 4. Choose system app display.

Step 5. Select messaging service.

Step 6. Choose to send premium SMS > Select inquire.

If the above method doesn't work, you can install 'Messenger' by Google as a replacement for your device's “Messages” app.
Source: Vas.Mytour.vn
