Wan interface set to Overide system DNS preventing domain lookup in Fortiguard DDNS?

I am trying to setup Fortiguard DDNS since I have moved away from a static IP, but I get an error like "Domain lookup failed" when I try to specify the "unique location" in the Fortiguard DDNS settings.  I am guessing it is because I have the WAN interface set to "override internal DNS"?  I am just checking to see if anyone knows this answer before I flip the switch and cause an outage!  :)  Thanks!