Error map with holes imported from blender

Hello, I just imported a map that I created in blender to roblox studio and it appears with many holes, what is wrong? Why does it look like this?

Does anyone know how to solve this problem?

Have you checked to make sure there are not too many vertexes to each of the single faces?

In that case, what would I do?

I don’t use blender, but I think this works.