After an Update 8.0 --> 8.1 you can not find any servers

Hello everybody, When I try to update 8.1 through the yast2 update module, that is not possible, getting a message that the server is unreachable and that I should try again or try anotehr server. Alas, this happens with all the servers available through yast2. I have tried stopping the firewall in case it was the cause blocking yast2 to connect but to no avail. Could it be that yast2 cannot see my proxy settings? I awould appreciate any input. Cleo