Sometimes you move a site to new hosting under a test alias to update or make changes. For example, the site skobki.com transferred to the domain skobki.com.superhostingblabla.com
As a result, disappears admin – you can not go to sitname.com/administrator
Solves simply – you need to prescribe live_site:
File configuration.php, in public $live_site = ”; prescribe the URL of the new site.
If this does not help – the second hint:
Try opening the admin directly through the index.php file:
Instead of http://sitename.ru/administrator
go to http://sitename.ru/administrator/index.php
Good luck!