Need Help Exporting and important blender low poly into roblox studio

Hello I am Making a booga booga type day and this is my first day using blender. I have built these things for my game but they are not importanting into roblox,I have been exporting as fbx which should work. Instead it just retrys until it reaches retry limit. Does anyone know how to fix this?

Are you using a mesh part when importing? I suggest to try obj.