I was having the same problem, the opening of my existing routes now works but I’m now getting the following error message:
“ HERE

Something went wrong while calculating the route. Please make sure all waypoint are on roads and reachable using the selected transport mode and try again.”

I’m having the same problems.

When Transferring Routes from MyRoute-app via Garmin Drive to Garmin XT.

I am using an iPhone 12 Pro and an iPad Pro running iOS 14.6, both are having the same problem.

After the recent update of Garmin Drive (updated on 6th May to version 4.15.02), when I send a route from MyRoute-app (any file type) via Garmin Drive to my Garmin XT the Garmin Drive App Crashes.
If I try and open Garmin Drive again it continually crashes and will not open again.
I have deleted and re-installed Garmin Drive and MyRoute-app but this does not solve the issue.
The Garmin Drive app works fine before I try and send the route from MyRoute-app, but after trying to send files from MyRoute-app , the Garmin Drive app again will not open and crashes.

I can send the route via a PC without any problems.

The file type I normally send is the .gpx 1.1 (Beta route, track, POI) but have the same issue with all the file types.
Any help would be greatly appreciated.