MediaWiki Visual Editor Parsoid 404 Error

...OK, sometimes one can get so wrapped up in the complexities of an issue the simple basic things are missed. And in this instance, among all the really good technical suggestions I read for correcting the issue, no one ever broached the below simple idea idea.

The Issue

I had successfully installed MediaWiki, an additional WYSIWYG editor, and as a final step I wanted to also configure the Visual Editor. To do that, one also needs to install the Parsoid service (daemon, well in CentOS 7, they seem to now favor the term service) and get them 'talking' together. So I did. I got the Parsoid service working, and...

Wait, ~~two~~ three side notes here. In my attempts to get the Parsoid service working I noticed that in my instance I could start the service and even if it didn't start correctly, it wouldn't notify me there was an error. I had to manually check the status to discover it wasn't actually started. So watch out for that item. For me in CentOS 7.4, the command is: systemctl status parsoid

Another item I noticed was that the config.yaml (for the Parsoid service) file was oddly picky about the spaces and tabs on every line, and if it wasn't happy, it wouldn't start. I had to copy and paste the tabs or spaces that preceded lines from other configuration lines where I had erased it on other lines.

OK, that reminds me, there's a third item I noticed too, which was that a lot of the documentation I was reading had configuration references that were for older versions. I was working with WikiMedia 1.3 and the Parsoid version available on 1.14.2018. A lot of the documentation I read referred to the localsettings.js file (Parsoid service configuration) which appears to have been deprecated at some point in favor of the config.yaml file.

The Solution

Well, it really isn't a solution per se, but rather a suggestion in the form of a question.

The Question

Have you checked your apache / HTTPD configuration?

I hadn't. And it turns out that was the issue. Specifically I had a simple typo in my httpd.conf file (I'm using CentOS 7.4, so the location and name of your Apache / HTTPD configuration file may vary. It may even be in multiple files.) that allowed me to view any page on the site, but didn't allow for editing with the Visual Editor.