Anecdote: I was having trouble accessing wordpress.org. When I started using Wordpress, I could access the documentation just fine, but then suddenly I couldn't access the website anymore. I dual boot Linux, so it wasn't Windows fault. I could ping them just fine. I tried three different browsers with the same issue. It's just that when I accessed the website, it would get stuck and not load at all, and sometimes pages would just stop loading mid-way.
Today I found the solution. Disable "Experimental QUIC Protocol" in Chrome settings.
This makes me kind of worried because I've had issues accessing wordpress.org for months. There was no indication that this was caused by QUIC. I just managed to realize it because there was QUIC-related error in devtools that appeared only sometimes.
I wonder what other websites are rendered inaccessible by this protocol and users have no idea what is causing it.