Laravel same code was working but now giving "Found empty contents" error

here is my log data

#0 /home/path/to/project/vendor/simplesoftwareio/simple-qrcode/src/SimpleSoftwareIO/QrCode/BaconQrCodeGenerator.php(74): BaconQrCode\Writer->writeString(NULL, 'ISO-8859-1', 1)

#1 /home/path/to/project/app/Http/Controllers/TicketDPController.php(1405): SimpleSoftwareIO\QrCode\BaconQrCodeGenerator->generate(NULL)

#2 [internal function]: App\Http\Controllers\TicketDPController->ImplementationSheetPDF('62374')

#3 /home/path/to/project/vendor/laravel/framework/src/Illuminate/Routing/Controller.php(54): call_user_func_array(Array, Array)

#4 /home/path/to/project/vendor/laravel/framework/src/Illuminate/Routing/ControllerDispatcher.php(45): Illuminate\Routing\Controller->callAction('ImplementationS...', Array)

#5 /home/path/to/project/vendor/laravel/framework/src/Illuminate/Routing/Route.php(212): Illuminate\Routing\ControllerDispatcher->dispatch(Object(Illuminate\Routing\Route), Object(App\Http\Controllers\TicketDPController), 'ImplementationS

via Chebli Mohamed