I have a XAVI outer model X7768r supplied by my ISP. The ethernet connections work fine. I purchased a laptop with wireless connectivity. I enabled the wireless connection on the router and the laptop sees the network connection. I click on connect, it uses a default WPA key and makes the connection only to drop it 5 seconds later. It tries 4 times and then gives up. What am I doing wrong. have I got to change the configuration on the router?