Oh what does this mean? HN blocks newly registered domains? Or Some people's firewall blocks newly registered websites?

Some people's firewalls. It prevents a lot of crypto scams and malware.

i.e. https://nextdns.io/ gives the option: Block domains registered less than 30 days ago. Those domains are known to be favored by threat actors to launch malicious campaigns

Equivalents exist on corp firewalls, etc. Something like 70% of malware and phishing points to domains registered in the last 30 days. So it is an easy way to mitigate the risk of the majority of attacks.

My corporate firewall also blocks archive.ph :-)

URL: https://archive.ph/nsO2H URL Categories: Anonymizing Utilities, Internet Services Reputation: Minimal Risk

Oh never know this one. I know that emails are blocked/pushed to spam if the domain is new.

But good to know this. In anycase, founderbeats.com is legitimate

I'm on a corporate network and am getting security errors, which likely means the corporate firewall has blocked it.

Oops. As someone was mentioning, new websites gets blocked some times.