Common issues
Navmesh settings reset when restarting editor
This is typically caused by editing the navmesh actor directly in your level. Instead of doing this, you should change the settings from the Project Settings menu instead.
The Project Settings values are used when the navmesh is rebuilt, which causes any changes to them in the level to be lost.
A secondary issue with this can be if you don’t have any Navmesh Agents configured. Instead of using the settings in the Navigation Mesh section of Project Settings, you may need to use the Supported Agents list in the Navigation System section instead.