I'm trying to register a new App ID inside iTunes connect web site, but when I've filled out the details and hit continue, it just comes up "Loading" and stays like that, any ideas?
Just for anyone else with the same issue. I tried another browser and it worked fine, so it's some kind of browser issue.
This was happening to me because I was using Safari "Private mode". When I turned back to "Non Private Mode" the problem was solved
I had AdBlock Plus and Ghostery running. Disabling both allowed it to work for me.
This happened to me one time too. I would check my internet connection first. Internet connection problem is something that happens frequently. After that i would go over all the information that you provided and see if there is a mistake somewhere.