VDAs are still trying to register with old DDCs post changing the list of DDCs

Post changing the Delivery Controllers list, VDAs are still trying to register with the old Controllers. Deletes the old Delivery Controllers FQDN on "ListOfDDCs" key in "HKLM\Software\Citrix\VirtualDesktopAgent\Policy" registry and restarts the Citrix desktop service, however the VDAs are still...