Can't access my local web server on Mac mini from Laptop after MX records update

I run a web server on my Mac mini on my Wi-Fi network. Somehow, after adding some MX records to my domain provider, I can no longer access my server on my laptop.

However, I can access it just fine on my iPhone and my iPad.

Monitoring websites outside my network also report that my website is up.

I tried cleaning website data from Safari and Chrome but both cannot access my website.

What am I missing?

[Re-Titled by Moderator]