If you have the Flight1 GTN installed, confirm that the active navigation source is set to Flight Simulator GPS by placing your mouse cursor over the GTN SD card. Right click on the SD card to toggle the active navigation source.
If you have the Flight1 GTN installed, confirm that the active navigation source is set to Flight Simulator GPS by placing your mouse cursor over the GTN SD card. Right click on the SD card to toggle the active navigation source.