The system is working as designed. All of your submitted links have been about the same company. You seem to be submitting them primarily to advertise this company, rather than out of any genuine intellectual curiosity. The one last week was flagged and killed, and likely your account was marked as spam.

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