import .gpx file on iphone greyed out?

Hi,
help please, I cannot import a .gpx file on an iphone, I'm stuck, any tricks out there?

I can browse to oneDrive, and see the .gpx files, but they are greyed out?
The status of the files are 'downloaded' onto my phone.

If I browse locations from the import file option:
- Same 'greyed out' result if I use iCloud Drive.
- Same result if I use the 'On My iPhone' folder.