NavMesh: AIController doesn't always reach certain positions in an obstacle-free environment

I’m facing a strange problem where from one position I can reach the destination and from others I cannot although there is no obstacles and the navigation is covering the whole area. This problem happens in two different situations

  1. The target and destination are on the same floor (same z)
  2. The target and destination are on different floors (different z). This is the most common problem no matter the size of the navMesh. although from first floor I can reach third floor and from third I can reach fifth, I cannot do it directly going from first floor to fifth floor.

I’m using “AIController” with “Move To Actor” method with no partial path (option unchecked) allowed.

This is the situation where target and destination are in the same floor. In the first image I can reach the destination. In second image when moving up a little bit (in the y-axis) I can’t reach the destination despite the fact that there is no obvious reason to stop me.

193439-fail.png

193440-success.png

What I tried till now

  1. change tile size uu as I thought there is a limit on the number of tiles that form the path.
  2. change cell size
  3. change cell height

Is there a limitation on how the navmesh and path finding works?
Whats else can I try to fix this issue?