New ask Hacker News story: Ask HN: Can someone tell me why my post got flagged?

Ask HN: Can someone tell me why my post got flagged?
2 by mjgs | 5 comments on Hacker News.
Hi all, A post of mine got “flagged”: https://ift.tt/3mQkmdi The string ‘[flagged]’ got added to the title. I am guessing this isn’t a good thing. It’s a link to a newsletter I create that contains javascript, tech and web developer links. It takes me a lot of time to prepare, and I think there is value there for others. As far as I am aware self posts are allowed, so what makes this particular link not allowed? Thanks, Mark