Hi!
I am very sorry for the late response, I missed your ticket by accident, it happens very rarely.
So, I have looked at the back-end and tried a few things. The plugin needs to be network activated in order to work correctly. I tested the automatic replacement, and indeed it causes a problem as the site is not rendered correctly.
I am not sure what exactly the problem is, because there are indeed no error messages. Can you please add temporary FTP access as well? I would like to debug the code directly, to see if I find anything. Thank you very much for your kind words and understanding!