Cerber changes embedded link in other plugin

Thanks Gioni, but what does that mean? I want the new hidden admin to be something like http://www.mysite.com/myhiddenname – but if I turn off “Disable automatic redirecting to the login page when /wp-admin/ is requested by an unauthorized request” then when a visitor goes to snoop at http://www.mysite.com/wp-admin it immediately redirects them to http://www.mysite.com/myhiddenname which seems to defeat the purpose of hiding the WP admin area. But I still don’t understand why a plug in looking for the normal wordpress admin_url breaks if it hasn’t been changed by Cerber.

That makes sense, but what I mean is why the other plugin would be trying to call the standard admin_url and failing once I install Cerber? Is there some other database field I should use instead of admin_url once Cerber is switched on and diverting to the new admin URL? So I switch on /myhiddenname and all works fine, and I want to leave the user with a 404 page if they navigate directly to /wp-admin….but if linking from inside this email that links to open a long URL string that includes admin_url, is there a way of inserting code that understands I am trying to navigate tp http://www.mydomain.com/myhiddenname/booking.php?