I connected my N800 with one WLAN access point. But I can not browser any webpage. The error message is "Server not found".

How can we resolve this problem?

Thanks!

What kind of wlan is it? Is it a proper open access point, or one you otherwise have access to, e.g. workplace, school? The reason I'm asking is that in my town there are lots of "open" access points, many of them are for real, that is, pubs, cafeterias etc. But others are just random non-encrypted networks of nearby offices and the like where they use just mac filtering. That means you'll get connected, but sometimes you'll get a question mark (no proper IP address), other times everything looks fine but you're not getting access to the internet. All depending on how they did the filtering.