Navmesh of SubLevel?

I have two levels one is the multiplayer level where its the starting level for hosting or joining a server and there’s no content, it is just an empty level simply for generating the starting screen for my game nothing else, and the other level is the main or first level where most of the content is and all the AI bases and all that stuff. In main level I also have a navmesh. The multiplayer level or world is the first world that will open because it will open the starting screen and whenever I host a server it opens the main level. But the thing is whenever I open it it always show the navmesh error message aka “navmesh needs to be rebuilt” so basically whenever I open my main world through my first world which is empty and simply for the start screen my AI won’t move cuz of the navmesh error can someone help me with this so that my AI could move again whenever I open the main level.