Screens does not go to sleep mode

Have a problem with my screens.
Sometimes they do not go to sleep. I have set the sleep time to 10min, and this work sometimes, and sometimes not. Maybe an open browser can do this? Is it other places than in power settings that control this function?
Are running 21.10, but as same problem on 21.04.

Found a solution after som Googling.
Typed this in terminal: xset dpms 300 600
Seemed to do the trick for now. Hope it works stabile.

Do look for any applications or processes running … anything that makes something change on the screen, write stuff to disk etc. Basically sleep stuff depends on the system thinking nothing is happening.

Make sure also you don’t have a popover displayed e.g. leave the menu being displayed. This will stop sleep stuff from occurring


Will also try to close all open windows after work.

Also see if a connected mouse isn’t disturbed on an unstable table or something. Got that a few times.

yeah, that could also make trouble.
This time I do not think the mouse was causing it. Discovered the screens was on when I came home after a 4 hour out of the house. But maybe the web browser was doing something since it was open as well.