Hi…,
Welcome to our new forum.
In latest FMS Data Manager Settings tab make sure the path for X-Plane is correct. If necessary navigate to where your X-Plane.exe is located.
In Addon Mappings , delete any X-Plane and X-Plane addon entries. Press Scan and you should see entries for X-Plane 11 and X-Plane 11 addons.
Press Save
In Addon List download as needed.
For information also see FAQ - Nav Data Out Of Date
Please let us know how you get on.
Cheers
Ian