HBO Go requires first email at Charter
I also had problems logging on, through Charter. After working with (a very helpful) consumer report representative, we determined that you have to use the FIRST email in the email account list, NOT the account holders email and password.
This suggests you may wish to add a fake AAA_name to your email list, to avoid sharing your info with other account users.
I too am disappointed with the lack of subtitles. My "fix" is to use over-the-ear sound cancelling headphones so as to not interfere with my hearing aids and to crank the sound to a level they can pick up. That doesn't work for thick accents, crappy diction, or heavy background noise but its better than using the little speakers in my MacBook.