A Navmesh is generated according to so-called "Nav Agents".
These
These Nav Agents are located in your Project Settings under the "Navigation System" Settings. There you can create a new Agent or edit existing ones.
To make your Navmesh go through narrow corridors, you need to change the "Navmesh"Nav Agent Radius". Keep in mind that if your NavmeshNav Agent Radius is smaller than your AI's Collision, the AI will probably get stuck!
