When I tried to add HBO, I was asked for my pin. I don’t remember ever creating one, so I used the common ones I’ve used before. None worked, so I created a new account (old one was created by late husband), new pin, and n o t h i n g is working.
When you created a new account did you link your Roku to the new account? What email address shows up under Settings->System->About? The only way to link a Roku to a new account is to perform a factory reset and go through the setup again.