Import .gpx file as ROUTE always fails

Dear all,
whenever I try to import a GPX file containing routing information, FiF is processing the data, but the result always leads to 0 import.
Example: I like to use SKYVECTOR for fast and convenient flightplanning. Via the application "INavCalc" I convert the plain link from skyvector into a GPX file.
Those files I cannot import into FiF. But in general that happens also with other sources of GPX files.
What do I miss here?
Kind regards,
Laotse
whenever I try to import a GPX file containing routing information, FiF is processing the data, but the result always leads to 0 import.
Example: I like to use SKYVECTOR for fast and convenient flightplanning. Via the application "INavCalc" I convert the plain link from skyvector into a GPX file.
Those files I cannot import into FiF. But in general that happens also with other sources of GPX files.
What do I miss here?
Kind regards,
Laotse