Uverse app doesn't work on Galaxy S4 or iPad

I just got Uverse TV yesterday. Today I tried using the app on my phone, but it does not work at all. Clicking 'Guide' gives me a loading message, then goes to a blank screen. All other screens are blank or 'not available at this time'. I tried reinstalling, clearing my cache, rebooting - still does not work. I switched to the iPad thinking it was am issue with my phone. Nope - same exact issue. Can you please tell me how to fix this?