laravel queue jobs processing attempts infinite

I am trying to use mail queuing in laravel 5.4.

Here's my route closure:

Route::get('mail/queue', function() {
    $job = (new SendEmailJob())->delay(Carbon::now()->addSeconds(5));
    dispatch($job);
    return 'Email will be sent shortly..';
});

And mailable class :

public function build()
{
    return $this->view('welcome');
}

Job class:

public function handle()
{
    Mail::to('abc@gmail.com')->send(new SendEmailMailable());
}

I run php artisan queue:work in the terminal.

And then load the mail/queue route. Output is sent to the browser instantly, and after 5 seconds job is processing.

But it seems like it is going forever, also attempts column increases until it hits 255.

Here's how it looks:

jobs table:

failed_jobs table is empty but the job never gets processed.

via Chebli Mohamed