Nothing Shows When I Click “Add New” in Themes

I am having a ton of issues. It is like my WordPress Dashboard can’t connect to the rest of WordPress. I go into Themes and click “add new” and it show nothing. I try to go into the live preview of ANY of my currently installed themes and it shows nothing. It is like the dashboard literally cannot load anything. What would cause that? And yes I already tried a different browser, cleared my cashe, disabled plugins, and so on.

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