Can you please link me a page or post where the plugin is enabled? As I can't see it anywhere I'm unable to tell where the problem might be. You can make a page and put the plugin shortcode inside of it so no other users will notice it, then just send me the url to that page.
It is also possible that some other plugin is conflicting with the related posts pro, or there is a syntax error somewhere on the site – I really can't tell.
You should also try to switch the script sources on the compatibility options panel from “Minified scoped” to “Minified”: https://i.imgur.com/ywfdD7B.png
I'm not sure if it will help, but it's worth a try.
If you could also provide temporary administrator and ftp access it would help me a lot, as identifying the problem is only the first step, but finding the source and the solution is much harder. I would run a line-to-line debugging on the related posts code if neccessary. You can do this by editing your initial post in this thread and filling out the proper fields. (it won't be visible to the public, just me and you)Best,
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