Dear nut-server maintainer,

the postinst maintscript uses pidof to check whether the udevd is
running. This is not safe in chroots and similar environments. pidof
will also be made non-essential shortly.

`invoke-rc.d status` should be used instead.

You can find a fix for this issue at part of the following MR (which
contains also various improvements to the maintscripts):

https://salsa.debian.org/debian/nut/-/merge_requests/10

Regards,