My laptop shuts down when I close the lid or press the power button?

This problem only started around last week, but I have also had it in the past.
Whenever I shut the lid of my laptop (which I have set for the laptop to to enter sleep mode), it seems to sleep normally (i.e. the fan turns off and the power button blinks to indicate the laptop is still on). However, it actually shuts itself off.
This also occurs if I let the computer idle until it would normally enter sleep mode, or if I press the power button (without holding it down).
In power settings I have the laptop set to go into sleep mode when I shut the lid or tap the power button, under all battery conditions. I have tried resetting the power settings, and have already used the system file checker to check for corrupted files (of which there were none). I have also used the power troubleshooter to fix issues and nothing happened.
I use an HP Pavilion x360 Convertible, and I run Windows 10 Home Edition (64 bit).
Any help would be very much appreciated. Thanks!

In the left lower corner search type power and open power and sleep settings > on the right pane click additional power settings > choose what closing the lid does > click change settings that are currently available > uncheck turn on fast startup

post an image into the thread

reboot and evaluate sleep and hibernation

recheck fast startup

reboot and evaluate sleep and hibernation

report into the thread any changes in sleep and hibernation.