Screen timeout no longer works on my S21 FE

[Wizardling]

When this first began happening on my month old S21 FE, a restart temporarily fixed it. But today when it happened again and I restarted the phone, screen timeout still won't engage after the set 2mins or even if I change it to 15secs.

I've never had this issue before with an Android phone, and I'm using the exact same third party apps as I was on my previous phone - a Redmi Note 10 Pro - which never had this issue.

This seems like a basic feature to get wrong, which is I suppose why none of my previous three Android phones ever suffered this, nor my iOS phones.

I'm particularly amused/disgusted because my year old Samsung monitor also won't sleep properly https://us.community.samsung.com/t5/Monitors-and-Memory/Monitor-won-t-stay-off-in-sleep-mode/m-p/262... 😄 Is this like a thing Samsung just can't get right?

[Samsung_Moderator · Accepted solution]

Hello, welcome to the Samsung Community. I understand your frustrations with your Screen Time Out feature not working properly and I will be more than happy to take a further look into this with you. 

Your device could be running an app that keeps the screen on while running the app. 

Running your device in Safe Mode will determine if it is a third party app causing the issue.

Power off your device 

Turn on the device and when the Samsung logo appears, press and hold the volume down button 

If done correctly, "Safe mode" will display in the bottom left corner of the screen (If "Safe mode" does not appear, repeat the previous steps)

Once you are in Safe mode verify if your Screen time out setting is working correctly 

To exit Safe mode simply restart your phone and it will reboot normally

You can clear the cache partition on your device:

While your device is off press and hold the volume up button and power button simultaneously 

Select wipe cache partition and confirm 

Once done power your device as normal 

If you are still experiencing issues after completing troubleshooting steps we recommend performing a Factory Data Reset: 

https://www.samsung.com/us/support/answer/ANS00062029/

[Wizardling]

After a second restart that morning, my S21 FE finally timed out its screen again. Till this morning when it's broken again. So now I need to find a whole day to leave my phone in safe mode? Or more like several days since this can sometimes not happen for multiple days?

That's just amazingly broken. On any full featured desktop OS it would take me exactly one terminal command to find out what is preventing screen sleeping. If I need to spend days in safe mode then that is a clear sign of a broken exceedingly poorly designed OS.