We're running Version 4.18.0 with few dozen different domains.
After setting up the newest site recently, we've discovered that we can't open the administration interface for that site.
Going to "http://www.newdomain.com.au/_admin" simply opens the front-end, without presenting the log in screen.
(The other sites are all still working as they always have.)
While i'm sure that we've set this site up exactly the same way as the others, clearly we must have done something wrong.
Can anyone suggest what might be causing this problem.
Any help or suggestions will be greatly appreciated.