I had the same problem, I think, I stumbled on what the issue seems to be – plain coordinate numbers inconsistency. What I did is leveled my landscape to zero (no mountains or valleys – made it FLAT), made sure that the destination point in the AIMoveTo function (in the EventGraph of the BP_AIController) is INSIDE the NavMeshBoundsVolume. Everything else as in the tutorial. It worked, hope this helps.