I finally gave in and updated by Note 8 after the 10 was released and now all of my calls are automatically rejected. Big surprise. Does anyone know of a fix for this other than buying a Note10 despite the fact that my Note8 is in perfect condition?
1. Turn off the device
2. Now switch your phone back on. Immediately you see the Samsung logo appear on your screen, press and hold the Volume Down key until the phone boots completely to the home screen.
3. You should now see a watermark caption "Safe Mode" at the bottom left corner of your phone screen. This will now disable all 3rd party apps.
If the issue doesn't occur with the device in safe mode then there is a third-party app causing this. You may have to delete your third-party apps one by one (starting with the most recent) until you find the one causing this.