I have exactly the same problem running x-plane 11 on my MacBook Pro. I bought 2 AFM G5's from X-Aviation and want to install them in a Cardinal RG bought from Carenado (which is running fine now). I had to update the Gizmo64 plug-in (latest version on their website) for the Cardinal to work. The G5 install into the main X-Plane folder went fine and the subsequent install into the Cardinal folder appeared to as well. No new Cardinal G5 showed up (should it?) in X-Plane, but a Skyhawk G5 did. When I start a new flight with either plane, the activate License popup appears. When I enter my X-Aviation name and PW X-Plane immediately quits as soon as I hit "Activate". What do I do next? I am new to X-Plane/X-Aviation and want to configure a plane similar to my real one. It doesn't look like this activate license issue was resolved. Please help. I have tried to contact X-Aviation through their support link and a ticket is opened, but I am told the only way to get a response is through this Forum.
Last line of the log file says X-plane crashed because of the Gizmo64 plugin:
0:06:40.291 G64: debug: No license for: (afm.GarminG5)
0:06:40.291 G64: debug: DRM: Showing window for update..
--=={This application has crashed because of the plugin: Gizmo64}==--
What Gizmo64 plug-in works?