Fatal error: Uncaught Error: Interface "Illuminate\Contracts\Mail\Mailable" not found in /home/sustaina/public_html/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php:28 Stack trace: #0 {main} thrown in /home/sustaina/public_html/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php on line 28