Screen not turning off. S10

[Macstew00]

My screen doesn't turn off and only turns off when it's charging, and it has nothing to do with my screen time out settings and always on display setting. Any help?

Have also reset my phone and still the same. 

[BandOfBrothers]

Try these troubleshooting steps @Macstew00 

• Safe Mode  > https://www.samsung.com/uk/support/mobile-devices/how-to-start-my-galaxy-device-in-safe-mode/ turns off downloaded apps and themes etc which may highlight an app or theme that's causing conflict. Alternatively long press the power off button and then ling hold on Turn Off to get to Safe Mode. 
• Clear Cache Files from the phone's System Partition Section  > https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to insert your earphones or hook upto a powered On Laptop or use a Tv's USB Port to access the Clear Partition Section. This may help with lag or stutters as this clears the phone of old/unused or broken cache files.There is also a Repair Apps option in the Menu System too { Possibly excluding the s²⁴ Series of phone's } 
• Back up and factory reset. 

If necessary contact Samsung directly to have the phone assessed at a Samsung Service Centre. 

If i can be of any further help please don't hesitate to ask  😎 

[AndrewL]

@Macstew00: You may wish to check your Smart Lock settings, to see if you have anything set up which might keep the phone unlocked under certain conditions (Settings > Lock screen > Smart Lock > Enter your PIN). To find out more, please take a look at the link below. 

https://www.samsung.com/uk/support/mobile-devices/what-is-smart-lock-and-how-do-i-use-it/