Filesystem.php - failed to open stream

I made multiple web-applications using Laravel so this is not my first production deply. However - I've bumped into a weird issue that I can't seem to find the answer for. As with all applications I've done so far - I copy/pasted all the files to the production server, set up the .env file, edited app.php and database.php in the config folder but i keep getting this error:

    ErrorException in ClassLoader.php line 412:
     include(/home/xxxxx/public_html/appname/vendor/composer/../laravel/framework/src/Illuminate/Filesystem/Filesystem.php): 
    failed to open stream: No such file or directory
    in ClassLoader.php line 412
at HandleExceptions->handleError('2', 'include(/home/xxxxx/public_html/appname/vendor/composer/../laravel/framework/src/Illuminate/Filesystem/Filesystem.php): failed to open stream: No such file or directory', '/home/xxxxx/public_html/appname/vendor/composer/ClassLoader.php', '412', array('file' => '/home/xxxxx/public_html/appname/vendor/composer/../laravel/framework/src/Illuminate/Filesystem/Filesystem.php')) in ClassLoader.php line 412
at Composer\Autoload\includeFile() in ClassLoader.php line 412
at Composer\Autoload\includeFile('/home/xxxxx/public_html/appname/vendor/composer/../laravel/framework/src/Illuminate/Filesystem/Filesystem.php') in ClassLoader.php line 301
at ClassLoader->loadClass('Illuminate\Filesystem\Filesystem')
at spl_autoload_call('Illuminate\Filesystem\Filesystem') in Application.php line 539
at Application->registerConfiguredProviders() in RegisterProviders.php line 17
at RegisterProviders->bootstrap(object(Application)) in Application.php line 203
at Application->bootstrapWith(array('Illuminate\Foundation\Bootstrap\DetectEnvironment', 'Illuminate\Foundation\Bootstrap\LoadConfiguration', 'Illuminate\Foundation\Bootstrap\ConfigureLogging', 'Illuminate\Foundation\Bootstrap\HandleExceptions', 'Illuminate\Foundation\Bootstrap\RegisterFacades', 'Illuminate\Foundation\Bootstrap\RegisterProviders', 'Illuminate\Foundation\Bootstrap\BootProviders')) in Kernel.php line 253
at Kernel->bootstrap() in Kernel.php line 144
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 116
at Kernel->handle(object(Request)) in index.php line 54

Now... I've tried everything i found on the web so far. Clearing cache, checking file permissions, running composer dump autoload, reuploading all the files - but nothing seems to help. It's a shared hosting with PHP v5.6 which already has several laravel applications running and they work perfectly. The only difference is that this one is laravel 5.3 and the other are 5.2.

I have no errors on my local dev machine.

Any ideas!?

via Chebli Mohamed