How to gather feedback/validate on forums?

Hello,

I've been trying to reach out to YouTubers by making posts on forums, which is my main customer target, and even though I'm not even linking out to my website (https://www.cast.watch), it usually ends up being flagged as spam/advertisement and being deleted, even though I'm only pitching the idea and trying to get some validation.

Is this tactic valid any more? what message format has worked for you in the past?