Fatal error: Uncaught Error: Interface 'Illuminate\Contracts\Mail\Mailable' not found in /home/kingelearn/public_html/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php:21 Stack trace: #0 {main} thrown in /home/kingelearn/public_html/vendor/laravel/framework/src/Illuminate/Mail/Mailable.php on line 21