Unable to send courses to Fenix 5X

Hi all,

1. I download GPX from the Internet
2. Add GPX to My Collection in Basecamp
3. Click right on the desired course, e.g. XYZ, and click on "Send to fenix 5X"
4. On my Fenix 5X there is no course XYZ. I have to add it via Mass Storage.

Steps 1-3 used to work but I have no idea why it's not working now (I have changed anything)...

Thanks a lot in advance.