Hi, In the Energy Saving Settings I disabled the logout session screen saver and the Dim screen, but my laptop logout alone the session when it's unused after 5 minutes. It's doing the same action when I'm watching video. Thanks for your support. Reproducible: Always
Please check the lock screen settings in System Settings → Workspace Behavior → Lock Screen and make sure it's turned off. Also, what version of Plasma is this? Since 5.3 watching a video should also block the lock screen.
Thank I did'nt see it as the dev team change the place of the lock screen config.