Others cannot access the content server.

I recently found out that Calibre has a content server to share ebooks with people. So I followed the steps to set it up using this guide https://manual.calibre-ebook.com/server.html

But, for some reason, every time I try to get someone on my home network or on a separate network to access the server it times out and they can't get on.

I've enabled port forwarding, made it so Calibre and its server are allowed through my firewall, and attempted to access it with 2 different browsers to no avail.

Is there any fix for this issue?