Hi,
If your settings look ok and no obvious apps settings is making the phone do this then one option is no other troubleshooting tips are forthcoming you could perform a Hard Reset / Factory Reset which takes the phone to how it came out of the box.
Please be aware this process also deletes data stored in the phones memory so do create a Backup if theirs some items you wish to retain.
"Press and hold Volume up, Home and Power buttons until the Samsung logo appears on the screen. Scroll to wipe data/factory reset by pressing the Volume down button. Scroll to Yes -- delete all user data by pressing the Volume down button. The phone will now reboot to the initial setup screen."
"This tutorial works with any model of Samsung Galaxy S5, so you should be safe using it with US carrier variants and all the other devices.
First thing that you need to do is open the Settings menu.
Go to ‘User and Backup’.
Tap on the ‘Backup and Reset’ section.
Press ‘Factory data reset’.
Confirm that you wish to Factory Reset your smartphone.
Enter the alternative password for your device.
Now you need to wait for your Galaxy S5 to complete the factory reset process."
If this does not resolve the issue and everything still looks ok then under the Samsung 24 Month Warranty you could approach Samsung uk Support Here.
Current Phone >
Samsung Galaxy s²³ Ultra 512gb Phantom Black.
