When trying to connect to the internet via my Airport extreme ATT says it detects a connection problem and goes through a password verification and change process. However it will not complete it? When I am plugged directly into the modem it works...

When trying to install my new AIrport Extreme I am having problems getting on the internet. I have verified my ATT account information. It autimatically pulled up after putting in my ATT user name and password. Then after having all green lights on both modem and router the webpage autimatically went to a internet problem ATT webpage. It had me download a internet client. But when trying to reset the password (which I had no idea why it was trying to do) it would not do it. AFter talking to ATT for an hour..and making a few little changes I got nowhere. I then hardwired the ethernet cable directly and had to rest my password before my hardwired internet would work. This verification went fine and it changed my internet password and started working again. Is there some kind of communication issue bewteen my modem and router? The modem works fine and I have connection. Just not through the router.

Thanks for your help.