HBO Go activation

I had HBO GO on my Xbox One and was with DirecTV for awhile so I had HBO access then we switched to AT&T Uverse but still have an HBO subscription. However, whenever I try to access HBO GO on my Xbox through their website and the link to AT&T Uverse it says my account does not have access to HBO. But when I go on my AT&T account it says I have access to HBO so what's the problem?