Out of Email Contact

I am in Toronto. On a computer. Connected to the internet. But...

Safari can’t open the page “http://mail.yahoo.com/” because it can’t find the server “mail.yahoo.com”.

How is that possible? In 2001, I spent 4 weeks in Ghana and Senegal and was able to check my Yahoo mail twice a day. Update: It turns out it was some "feature" of Safari that caused the problem. Not that I'm a Microsoft booster, but it gives me pleasure when it turns out that Mac stuff isn't the bees knees.