I have a Garmin 5s Plus, when I got to sync my audiobook I can see it in my library. I click it to transfer, it says transferring complete after a couple of minutes. When I go into my device on the garmin app it shows that is on my watch however when I go to sync it again it says I have no audiobooks avaliable. When I look at what is on the watch it says its an unknown file with 1 track. What am I doing wrong?