New Modem - Uverse Receiver Not Connecting

I got a new modem delivered from ATT and hooked up yesterday.  Also changed my long ATT.... network name to something easier and new password.  Everything is working great, except that our main Uverse receiver/TV is not connecting.  Our secondary receiver/TV is working to watch a show, but no DVR features and no ability to record, pause, rewind, etc.  I know that will be resolved once we get the main Uverse receiver online.  

I have unplugged everything, rebooted, restarted, reset, etc. etc. numerous times.  I still get a blue band saying "video unsupported" and then it goes to the Uverse logo and the line on the bottom saying something to the effect of Uverse not connected.  Please restart receiver.  Which I've obviously done like I said.  

I'm on chat with ATT right now, but this has to be an easy fix.  

How do I connect that box with a new network name and password?  I can't find it anywhere.  
OR... should I change network name and password back to the old one and see if that works and go from there?  

Much appreciated.