Nokia Nseries :: N8 Does Not Connect Via Wifi

My N8 does not connect to websites via wifi, in general, 90 % of the times it does not open any web page, either with the default web browser or Opera. However, the phone connects to the wifi network, and Skype for instance always works via wifi, but normally, you cannot go to any webpage or use other programs needing the internet.Surprisingly,sometimes it does connect (10 % of attempts), while nothing was changed in the router or anything. It does happen with any wifi network.