fix: Handle null response in SaleController index method

- Add try-catch block to handle null response from API
- Log errors and return appropriate HTTP responses
- Update error message in 503.blade.php to show exception message if available

resources/views/errors/503.blade.php

@@ -9,7 +9,7 @@
     <div class="text-center">
         <h1 class="font-bold text-orange-400 text-8xl">503</h1>
         <h2 class="text-3xl font-bold text-white">Unavailable</h2>
-        <p class="mb-8 text-stone-300">The page you are looking for is unavailable.</p>
+        <p class="mb-8 text-stone-300">{{ $exception->getMessage() ?? 'The page you are looking for is unavailable or under maintenance.' }}</p>
         <a href="/" class="px-4 py-2 mt-4 text-white bg-orange-400 rounded-md hover:bg-orange-500">Go back to the homepage</a>
     </div>
 </div>