Use singular controller

app/controllers/admin/dashboard_controller.rb

@@ -0,0 +1,8 @@
+module Admin
+  class DashboardController < BaseController
+    authorize_resource class: false
+
+    def show
+    end
+  end
+end

app/controllers/admin/dashboards_controller.rb

@@ -1,9 +0,0 @@
-module Admin
-  class DashboardsController < BaseController
-    authorize_resource class: false
-
-    def show
-      redirect_to [:admin, :domains] if can? :show, Domain
-    end
-  end
-end

config/routes.rb

@@ -149,6 +149,8 @@ Rails.application.routes.draw do
 
   # ADMIN ROUTES
   namespace :admin do
+    root 'dashboard#show'
+
     resources :keyrelays
     resources :zonefiles
     resources :zones, controller: 'dns/zones', except: %i[show destroy]
@@ -258,8 +260,6 @@ Rails.application.routes.draw do
     authenticate :user do
       mount Que::Web, at: 'que'
     end
-
-    root 'dashboards#show'
   end
 
   devise_for :users