What would keep me from visiting a webmail based site?

[Nocturnal]

I am on my work computer. I'm not on a LAN or anything. I have a DSL connection with Windows XP. I can't get to my ISP's webmail page. Everyone else I've spoken with can get to the page.

I'm wondering why I can't get to it. HELP!

 

[igowerf]

What happens when you try to go there?

 

[Nocturnal]

It says the URL doesn't exist. Or it gives me the error like when you don't have an active internet connection.