Also, after it was vouched for, the submitter posted or requested comments from sockpuppet accounts – just like they’ve done in the past. The fake accounts and comments probably justify banning the domain.
And to wanshao: this isn’t the place to try to promote your stuff, let alone with fake comments. Read https://news.ycombinator.com/newsguidelines.html . The platform manipulation that worked for you the last time will not work again.
When you submitted another link to the same company, it was automatically marked dead to hide it from the rest of the community. From your own account, it is not marked dead, but if you log out presumably it would show as dead. This particular one was vouched for by another user, and thus is no longer dead.
You seem genuine, but you also seem like you don't understand how HN works. You are abusing the system and acting like a spammer. While this might be a genuine misunderstanding on your part, other than asking polite questions your actions are indistinguishable from a bad actor. Stop submitting until you better understand the rules: https://news.ycombinator.com/newsguidelines.html