Webpage won't function

Hi there, I really need some help..

I can't make this website work on my mac: Login Feltet.dk admin

I have no troubles logging in to the site, but when I hit the green button (I've attached a picture of the screen so you can see) the site starts to load, but then just stops.. And nothing happens. I then have to refresh the browser, but then I just return to the main screen (picture number 2).

Do you guys know what it might be? I have been struggling with this problem for some time, and it really bothers me!!

Thanks for your time!

No one's got an idea?

Have you tried different browsers

Yes, I've tried almost all possible browsers. It worked a short time in Chrome, but not anymore..