it would help if you described what operation (mode maybe) you are attempting immediately before you get the pop-up e.g. dragging a route to a different road, adding a waypoint, saving a file to a particular format, ad infinitum ...
Just trying to do a route from A to B . Rotterdam to Annecy
and its saying
The route calculation seems to take very long. You can try resolving this by shortening your route or by adding a waypoint between your current waypoints.