I have the Galaxy S20 Ultra, and up until the update was pushed out onto my phone on June 5th, the Auto Restart was functioning properly. I have it scheduled 3 nights a week for 3AM. But now its not working.
Have you tried wiping the cache partition on your device?
The system cache partition stores temporary system data. It's supposed to allow the system to access apps more quickly and efficiently, but sometimes things get cluttered and outdated, so a periodic cache clearing can help make the system run more smoothly.
Give these steps a try to wipe the cache partition on your device:
Turn off the device.
Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
When the Android logo displays, release all three keys.
An 'Installing system update' message will show for 30 - 60 seconds before the Android system recovery menu options appear.
Press the Volume down key several times to highlight wipe cache partition.
Press Power key to select.
Press the Volume down key to highlight yes, them and press the Power key to select.
When the wipe cache partition is complete, Reboot system now is highlighted.
Press the Power key to restart the device
Please let me know if you continue to experience these symptoms.
Were you able to follow the steps on how to wipe the cache partition provided by @SamsungCole? If you are still experiencing the same issues after performing this step, I would try testing your device in safe mode to see if a third-party app may be causing this to occur.
This step will temporarily disable all your third-party apps, but none of your personal data will be deleted. Your customization settings (Wallpaper, Themes, et cetera) will be reset to default once you exit this mode.
Please follow the steps below:
1. Turn the device off.
2. Press and hold the Power key past the model name screen.
3. When "SAMSUNG" appears on the screen, release the Power key.
4. Immediately after releasing the Power key, press and hold the Volume down key.
5. Continue to hold the Volume down key until the device finishes restarting.
6. Safe mode will display in the bottom left corner of the screen.
7. Release the Volume down key when you see Safe Mode.
8. To exit Safe Mode, restart your device.
Let us know how your device responds after performing this step!
You would want to leave it in Safe Mode overnight to test if the issue occurs overnight. If it does not restart this would indicate there is an app causing the issue.
Thank you for confirming. The final step in troubleshooting before looking into other options would be to back up all files on the phone and do a factory reset. https://www.samsung.com/us/support/answer/ANS00062029 Once you do this, test the AutoRestart feature again. If it still does not function properly, please send a private message with the model code and IMEI number. http://bit.ly/2XERsky