Imported track Route not found

I often import tracks from a PC Software. I convert them with the app "Route Importer".
So I have them under "My Places" "My Routes". I load them and have many Routing Point.
When I calculate the route I often get the message "Route not found".
Is there a possibility to recognizes which Routing Point is the problem?
Up to now I dismark manually some routing points until the calculation works, but that can´t be a solution!!
Why can´t there be a hint "Route not found at Waypoint xyz"??