You see, lots of spammers and scammers will use scripts to set up accounts. The CAPTCHA and Robot check is to ensure a script isn't running, and that it's an actual human using the form. That's actually kinda standard procedure these days. Welcome to the Internet 2018.
As for the "Roku pin # to streamline HBONOW" thing, I'm not sure what you're asking. If you'd explain the steps you took and the exact wording -- don't paraphrase -- of the message, that would be helpful.
You see, you could be referring to a couple of things. One is the PIN that may be required when you attempt to add an app to your Roku. That would be the case if the Roku account owner set up. If you are the account owner, you set that up.
Log in to your Roku account at https://my.roku.com and look at PIN preferences. That is what determines whether it asks you for a PIN to add apps, such as HBO NOW.
The other thing that many apps use -- I don't use HBO NOW so I don't know if that app works that way -- is they may present an authentication code to use to authorize your app through your content provider.
If this solve your issue, great. If not, provide information in a calm, clear, concise manner that will help troubleshooters analyze and solve the issue.
Basil https://www.basilsblog.com/ Roku Ultra (4660) Apple TV (5th gen), TiVo
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