Cannot login to back office admin panel

[Nij]

My shop is live : shop.sheepdog-training.co.uk    but I cannot access the back office/admin panel to make changes. After switching to debug mode, when I try to access the BO the page returns the following:

 

Notice: Undefined index: adminnotfound in /homepages/9/d461631471/htdocs/clickandbuilds/PrestaShop/shop/classes/Dispatcher.php on line 335

Fatal error: Uncaught Error: Class name must be a valid object or a string in /homepages/9/d461631471/htdocs/clickandbuilds/PrestaShop/shop/classes/controller/Controller.php:134 Stack trace: #0 /homepages/9/d461631471/htdocs/clickandbuilds/PrestaShop/shop/classes/Dispatcher.php(359): ControllerCore::getController(NULL) #1 /homepages/9/d461631471/htdocs/clickandbuilds/PrestaShop/shop/backoffice/index.php(58): DispatcherCore->dispatch() #2 {main} thrown in /homepages/9/d461631471/htdocs/clickandbuilds/PrestaShop/shop/classes/controller/Controller.php on line 134

 

 

Any help would be greatly appreciated. 

 

Edited January 25, 2019 by Nij (see edit history)