Hi, you could uncheck “Use Pathfinding” and set the movement type to flying.
Normally the AI uses the Navmesh to find a way to the target. If there’s no such way the AI won’t move.
So you can either build in a way for the AI to reach it’s target (a stair or ramp) or ignore the Navmesh. By unchecking “Use Pathfinding” the AI will ignore the Navmesh and move in a straight line to the target. In order be able to reach the target you should then set the character movement type of the AI to “flying”.
When the AI reaches the target you can set the movement type back to “walking”.