On Wed, 2021-04-21 at 17:05 +0800, Qiyu Yan wrote:
By default, Super+L should be the shoutcut for screenlock. In your case, if you didn't change the shoutcut, that means your screen lock is not working at all.
I don't think that's the default for all desktops. On mine, using MATE, it's CTRL ALT L. And I don't recall setting that combination, myself.