Step one error

I’m trying to install this plugin. When going through the setup, I click through the first screen that asks for domain details and then accept terms and conditions. When I click ‘next’ it takes forever to load and then goes to a 404 page not found error. I’ve tried deactivating, deleting and reinstalling the plugin, but there is no difference. I need some assistance with this please.

Thank you!

The page I need help with: [log in to see the link]