I have a solution for this and will raise a PR shortly.

The cause is that the sqlzoo.net URL forces a redirect which Edge and Firefox (the browsers I tested) do not seem to follow. I was able to get the page to render in Chrome, but only after clearing my local cache.

sqlzoo has a permanent link on their page that forces the latest revision of the site. However, this would become stale very quickly. Instead, it looks like they have an option of sending a URL param to turn the redirect behaviour off.

https://sqlzoo.net/w/index.php?title=SQL_Tutorial&redirect=no I tried this in all the browsers I tested and it works as expected.

PR that addresses this issue here #29167

@Hossam-Allam thank you for raising this issue!

@Captainmango thanks for putting up the PR, I'll assign you to this issue, but so that you know for the future we prefer people to not put up PRs for opened issues without being assigned.