Using Amazon Firestick with AT&T U-verse

     I recently moved and the only choice for internet/tv connection was AT&T (previously had COX Cable).  My Amazon Firestick worked fine with COX.  But I'm having issues getting the connection to work with AT&T.  I got the Firestick to show up properly.  My network name shows up on the screen.  I enter my password and it attempts to authenticate.  But it fails every time and simply says, "Authentication problem."  Then it disconnects and tries again.  The password is correct so that's not the issue.

     AT&T Tech support/chat attempted to help me by instructing me to adjust firewall settings.  But that also failed.  After that, they connected me to ANOTHER level of tech support.  They assured me that they could resolve the issue but their support was a paid service so I'd have to subscribe to it!  Wow. 

     Why in the world is this so difficult?  Any help is appreciated.