Issues resuming Win10 from sleep

Recently my Win10 machine has not been resuming its sleep state back to the main login screen for windows.

It does not display anything on my computer screen, then reverts to auto rebooting after a couple of mins.

Not sure what the reason behind this is.

On a rare occasion, my system will awake from sleep and go straight to the windows login screen. But this is very rare now.

Any ideas or steps to diagnose the problem?