I did some more testing on a freshly installed WP site and discovered that the issue is actually something else.
The plugin WORKS fine with SSL. The problem is that the redirect slugs are NOT interchangeable between HTTP and HTTPS.
For instance, if my WP site is installed as a HTTPS site with domain https://domain.com….
Doing this…
Request: /slug/
Destination: anywhere
…will work as long as https://domain.com/slug/ is called.
However, https://domain.com/slug WILL not work and will result in a 404.
The workaround is to enter a second redirect for the HTTP with the full URL path like this:
Request: https://domain.com/slug/
Destination: anywhere
Then this will work when http is called.
If the dev sees this, is it possible to add a feature where HTTP and HTTPS can be interchangeable?
Or is this something that’s more related to htaccess? Please advise. I’d definitely do not want to enter two sets of redirection rules each time…