When I request the reverse delegation for my ASSIGNED PI IP range, I receive the an authentication error.

If you receive an authentication error as follows:

***Info: Authorisation for parent [inetnum] XXX.XXX.XXX.XXX - XXX.XXX.XXX.XXX using mnt-lower: not authenticated by: RIPE-NCC-HM-PI-MNT

You are being asked for authorisation from the 'mnt-lower: RIPE-NCC-HM-PI-MNT' field that is present in your ASSIGNED PI inetnum object. In order to bypass this, you should add the following line to your inetnum object:

mnt-domains: [your own maintainer]

This will give the above maintainer the authorisation for requesting the reverse delegation for this IP range.