Cannot sign into HBOGO on cellphone

I'm trying to use the HBO go app and when I choose Xfinity as my provider it immediately gives me an error without even giving me a login screen. The stocked working the couple of months ago and I've only just know decided that I can't fix it myself. The actual error is:

Signed Out
We’re having trouble verifying your access to HBO GO with your TV provider. If you continue to have this issue, contact your TV provider for assistance

And, YES, I have already removed and reinstalled the HBOGO app.

Thanks!