message “nous n’avons pas trouver de connexion entre au moins 2 waypoints”
Hello PLD and welcome.
Kurviger tries to calculate a route from waypoint to waypoint. In your case it failed at some point.
Possible reason, that a waypoint is placed about > 5 km from the next routeable way (for example one point is in the middle of some lake).
Another reason is, a waypoint is placed on a way, which is a oneway, and for some reason it is not possible to drive through the oneway (some construction site at the end). You are in a trap, as forward is not possible and backwards is not allowed.
A third one I know, is when the planning crosses borders of continents. Often an issue with Turkey. Sometimes you can place some points in Turkey, sometimes points are failing.
Best way to solve the issue to delete the last placed waypoints until the route can be calculated (brute force method by @t00thl355 
).
Hi @PLD,
As @Toffel already explained the error can have multiple causes. Please try the suggested solutions and see if that solves the problem already. Also have a look here: most common errors.
If possible, you could also share what you’ve got so far, so someone can have a look. This is how.