Xubuntu 18.04.2 When I lock screen, lock screen not appears it directly goes to dark screen/sleep, it doesn't wake up after I press any key or Esc.
When the computer is idle for a while and it gone to screen lock, I don't know it goes to sleep mode or what!
This situation if I toggle Caps Lock button, caps lock indicator light is on/off. but display is still dark. If I press power button it directly goes to shut down (no display but I can understand it is going to shut down if I click Esc some msg are shown...) Then I power it again and work.
btw, I am doing
Ctrl+Alt+F7 right now, but this is irritating, need a permanent solution.