add validation rule

src/Services/Users/UserRegistration.php

@@ -61,7 +61,7 @@ public function getValidationRules(): array
         return [
             'username' => ['required', 'unique:users'],
             'password' => ['required', 'min:6', 'confirmed'],
-            'email' => ['required', 'unique:user_attributes'],
+            'email' => ['required', 'email', 'unique:user_attributes'],
         ];
     }