Laravel custom class not found?

Im getting the follow up error "Class 'Martins\ArtisanGUI\ArtisanGUIServiceProvider' not found", i already wwrite it in config/app.php like Martins\ArtisanGUI\ArtisanGUIServiceProvider::class and recheck namespaces, and composer but i can't figure out what is wrong.

Composer And Provider Code

via Chebli Mohamed