Hi @hewittig,
This happens when servers kill the import process, usually due to lack of php memory, or the process taken too long.
If you try again with the main file, when you get that error just hit back in the browser and carry on with the process again. It may take 10+ goes, but it will eventually all go through.
For the mobile menu, you have the option to set a different menu, or just use the main menu as you used for the main navigation location.
You’d need to update the URLs for the features menu, as these are linked to our demo site.
Hope that helps.
– Ed