Sometimes some gpx imports at explore.garmin.com dont work - then try to import it at your connect.garmin.com webpage as a course. You can then import the course from explore.garmin.com
The newest Beta version can import GPX files on the phone. It even works better than in the web browser, because it keeps all of my waypoint icons, instead of setting them all to the blue flag.
With Garmin Explore App version 2.9 which was just released, it is now possible to import GPX files into the app from the smartphone. This article from our Support Center has more information Importing GPX Files in the Garmin Explore App.
