is there anything on the host’s side that could prevent WP plugins from working?

I’m using a plugin that does 301 redirects to the homepage for any pages that give a 404 error. I have this plugin working on dozens of sites, but I recently am using a new host for one of my sites and the plugin is not working.

Since everything else is basically the same, I cannot think of a reason why it would not work unless there is something on the host’s side, or some sort of permission error or something somewhere.

The plugin installs and activates just fine, it just doesn’t redirect any 404 errors.

Does that sound like a host and/or cPanel setting somewhere?

It’s the same version of WP as my other sites.

Also possibly relevant, it’s not showing the normal WP theme 404 page, but is instead showing this:

Not Found

The requested URL /sdf was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

SOLVED – changing the permalink structure from default to /post-name/ fixed it

How bizarre.

Why would the default permalink structure affect WordPress’ 404.php?