Apache is what's serving the error page. It's whatever is behind Apache that is failing

I've had an Apache server running on a decade old laptop on the HN front page, serving a custom PHP+Mariadb blog without caching, works just fine. It's big projects like WordPress that reliably go down from more than a handful of visitors per minute with bursts to a few in one second, if you don't have a caching layer that turns it into the equivalent of a static page generator