@GlimpseOfDawn IK that it needs to be in the current level and it is in Current Level, I created a new project with the same map but without World Composition and I can Choose the landscape and fallow the tutorial, but now I founded another glitch, when I try to Apply Spline to Landscape its make a part of the map black.
And yes I Also tried doing it with ony one road selected.
Still not working in World Composition, I’m using ue4 4.21