Importing an osm file into Ariadne gps?

iOS and iPadOS
Hi I bought the in app purchase and so far everything worked fine. So I tried to import an osm file. I called it ls.txt and put it into ariadne via itunes. But after going to import from loadstone and pressing ok, the iphone works for a moment and goes back to the list of favorites. Then there's some kind of warning which disapears to quickly to be read, and then the app closes. I remember vaguely having some trouble when importing an actual loadstone file in autumn, but It worked at the third try or so... Any suggestions? Guenni