ESPN+ how to stream on ipad or iphone

WE paid for a year's subscription to ESPN+ so we could stream ESPN+ on our iphones and ipad.  We have ATT UVerse as our internet and TV provider...Cable.....  In the past we could stream SEC network games and on demand past games from ESPN+ on our phone and ipad.  WE are unable to open up ESPN+ at all.  It says "unauthorized, contact your internet provider" or a similar error message.  We have spent hours and hours online with ESPN+ support, Uverse Support, and Apple support.  HELP!!  How do we make this work?