Dear Maintainer,

Recently (probably linked to the upgrade to bullseye), the following started to
happen:

When I ask to suspend the machine, the machine does not suspend but instead I
get a dialog box saying:

    None of the screen lock tools ran successfully, the screen will not
    be locked.
    Do you still want to continue to suspend the system?

I'm running `xscreensaver` as screen locker.

The same dialog box pops up in my account when I suspend the machine from a
session opened by another user.  In that case the machine does suspend, tho,
and I just see those dialog boxes later when I wake the machine up and log into
my session.