Error when trying to import a RideWithGPS .FIT file into Garmin connect

I found a route in RidewithGPS, and exported it into a .FIT file.  When I try to import that into Garmin Connect Web (on a Mac), I get an error: "Your course cannot be imported. Something is wrong with this file.".  I am hoping someone can help me understand how to circumvent this issue.

Thanks,

George