diff --git a/app/Enums/UserRole.php b/app/Enums/UserRole.php
index e8770e5..c8f7166 100644
--- a/app/Enums/UserRole.php
+++ b/app/Enums/UserRole.php
@@ -21,16 +21,16 @@ enum UserRole: string implements HasLabel
 {
     case Administrator = 'administrator';
     case Agency        = 'agency';
-    case DomainManager = 'domain-manager';
-    case GroupManager  = 'group-manager';
+    case DomainAdmin   = 'domain-admin';
+    case GroupAdmin    = 'group-admin';
 
     public function getLabel(): string
     {
         return match ($this) {
             self::Administrator => __('Administrator'),
             self::Agency        => __('Agency'),
-            self::DomainManager => __('Domain Manager'),
-            self::GroupManager  => __('Group Manager'),
+            self::DomainAdmin   => __('Domain Admin'),
+            self::GroupAdmin    => __('Group Admin'),
         };
     }
 }
diff --git a/app/Filament/Pages/ManageZimbraSettings.php b/app/Filament/Pages/ManageZimbraSettings.php
index 7ff9f56..27828a1 100644
--- a/app/Filament/Pages/ManageZimbraSettings.php
+++ b/app/Filament/Pages/ManageZimbraSettings.php
@@ -49,6 +49,8 @@ class ManageZimbraSettings extends SettingsPage
                 ->required()->label(__('Admin User')),
             TextInput::make('adminPassword')
                 ->password()->required()->label(__('Admin Password')),
+            TextInput::make('defaultDomain')
+                ->required()->label(__('Default Domain')),
         ]);
     }
 
diff --git a/app/Filament/Resources/UserResource/Pages/CreateUser.php b/app/Filament/Resources/UserResource/Pages/CreateUser.php
index 9e068cd..3378ee3 100644
--- a/app/Filament/Resources/UserResource/Pages/CreateUser.php
+++ b/app/Filament/Resources/UserResource/Pages/CreateUser.php
@@ -10,7 +10,7 @@ namespace App\Filament\Resources\UserResource\Pages;
 
 use App\Enums\UserRole;
 use App\Filament\Resources\UserResource;
-use App\Models\Domain;
+use App\Settings\ZimbraSettings;
 use Filament\Forms\Form;
 use Filament\Forms\Components\{
     Select,
@@ -39,7 +39,7 @@ class CreateUser extends CreateRecord
             TextInput::make('name')->required()->label(__('Name')),
             TextInput::make('email')->email()->required()->unique()
                 ->endsWith(
-                    Domain::all()->pluck('name', 'name')
+                    app(ZimbraSettings::class)->defaultDomain
                 )->validationMessages([
                     'unique' => __('The email address has already been taken.'),
                     'ends_with' => __('The email address does not belong to any domains.'),
diff --git a/app/Settings/ZimbraSettings.php b/app/Settings/ZimbraSettings.php
index 668429a..2367130 100644
--- a/app/Settings/ZimbraSettings.php
+++ b/app/Settings/ZimbraSettings.php
@@ -25,6 +25,8 @@ class ZimbraSettings extends Settings
 
     public string $adminPassword;
 
+    public string $defaultDomain;
+
     public static function group(): string
     {
         return 'zimbra';
diff --git a/database/settings/2024_04_16_025540_create_zimbra_settings.php b/database/settings/2024_04_16_025540_create_zimbra_settings.php
index 1e06338..583c8f8 100644
--- a/database/settings/2024_04_16_025540_create_zimbra_settings.php
+++ b/database/settings/2024_04_16_025540_create_zimbra_settings.php
@@ -9,5 +9,6 @@ return new class extends SettingsMigration
         $this->migrator->add('zimbra.serviceUrl', '');
         $this->migrator->add('zimbra.adminUser', '');
         $this->migrator->addEncrypted('zimbra.adminPassword', '');
+        $this->migrator->add('zimbra.defaultDomain', '');
     }
 };