If you have a lot of migrations of service inside yours, or somebody else company, you will sometimes need to delete some obsolete DHCP servers authorized in AD. You will probably be able to se them when you you open DHCP management console and authorize it from there. but in some cases they will be deleted from AD, but authorized in AD. when that happens you will need to delete them with help of ADSI edit. Lets go step by step.
1. Open ADSI edit and connect to Configuration Naming Context
2. Browse to Net Service node where you will get list of DHCP authorized servers together with DHCProot entry. In my case I have one bogus entry (you can recognize it by random GUID at the end and CNF). CNF means conflict.
3. Right click entry and then delete it.
This action solve orphaned and conflict entries for DHCP authorizations