DBus seems to resolve user IDs directly via glibc, circumventing nscd. In more
advanced setups this leads to user's coming from LDAP or SSSD not being
resolved by the dbus system bus daemon. The effect for such users is, that all
access to the system bus (e.g. busctl or nmcli) is denied.
Adding the respective NSS modules to the service's environment solves the issue
the same way it does for nscd.