It's been doing this since yesterday and it keeps giving me this same result. Whenever I press on "Add External File" it gets stuck on the "Creating..." and doesn't create anything no matter how much I wait. I've tried reloading the page multiple times, clearing the cookies, changing browser... none of it worked.
Before anyone asks, this happens as soon as I click on "Add External File", I haven't loaded any files or touched anything else outside of that.