I can’t seem to enable the copyright text / pasting custom text.
I can confirm both options are enabled and text is present in the “copyright text” and “custom text” fields.
However, when attempting to copy and paste from the site, it pastes whatever was in the clipboard prior to copying the text i.e. it’s not actually copying/pasting anything.
Also, we checked and noticed that you are using Cache plugins. So, please make a DB backup for your safety (you can use UpdraftPlus). Then, clear all the caches.
Make sure the cache is excluded on the page where the copy protection is enabled.
After clearing the caches, please try to check the case with either the Incognito mode or another browser/device.