Lapsus is a program created to let laptops users use many of the
features of their laptops which are supported by Linux. For now,
there are two hardware-specific backends - Asus and IBM, and one
'generic' backend for all unsupported hardware.

Every user, who wants to use lapsus, needs to be in a group called 
'lapsus'.  You can add that group via 'groupadd lapsus'.
Alternatively, if you want to use a different group, you can edit
/etc/dbus-1/system.d/lapsus.conf to specify a different one:
Change the line that reads like this:
  <policy group="lapsus">
to whatever group you wish to use; for example, the 'power' group:
  <policy group="power">