Hi Scott,
Welcome.
First check FAQ - Nav Data Out Of Date, particularly para 3.
If no joy,
In FMS Data Manager Settings, Make sure your have the latest Version
If not, please uninstall, download FMS Data Manager and run.
In FMS Data Manager Settings, Check you have the correct X-Plane 12 path.
In Addon Mappings , select and Remove X-Plane 12 and X-Plane 12 addons. Press Scan. If X-Plane 12 and X-Plane 12 addons are not detected, use +Add to add them manually.
In Addon List select and Update X-Plane 12 and X-Plane 12 addons.
Please let us know how you get on.
Cheers
Ian