My page does not load, help?

What does it mean when im waiting for a page to load and it comes out .. HTTP Error 504: Gateway Timeout server, while acting as a gateway or proxy, did not receive a timely response from upstream server it accessed in attempting to complete the application. I'm trying to climb a website to get my picture message from Vodafone, but every time I click I get the picture that comes up.

It means that you know the website is there, you can talk to the website. But the website is having problems of its own because it is too slow, or not right setup. Just try to go there again more later. Not much you can do but try to go there again later, probably no one else can go to the site and if you need to get forever to load.