I've been trying for over a year to log into it and other online services that ask your premium TV content provider. I've tried every suggestion on the forums and spent way to much tome trying to work through it with tech support on the phone and through Facebook. When I had Directv I never had a problem with HBO go. It is getting maddening.......
Are you using the same id that you use to access your Verizon account online?
A bunch of things lead to problems loging into HBO GO and many other Online Channel sites.
The general way it works is for you to go to HBO GO site. Ask to look at something and it switches in a FRAME pointing to VERIZON and you signin. Verizon stores some information in flash and returns. That information must still be there so that HBO accepts you as authorized.