Laravel Mail Job无效

Question

我正在尝试为我的laravel应用程序创建电子邮件验证。为此我已经用这个内容设置了一份新工作：

class SendVerificationEmail implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    protected $user;

    public function __construct($user)
    {
        $this->user = $user;
    }

    public function handle()
    {
        $email = new EmailVerification($this->user);
        Mail::to($this->user->email)->send($email);
    }
}

此剂量不起作用。如果我运行php artisan queue:work并执行该作业，控制台会在无限循环中告诉我：

[2018-03-26 15:50:25][1] Processing: App\Jobs\SendVerificationEmail
[2018-03-26 15:50:26][2] Processing: App\Jobs\SendVerificationEmail
[2018-03-26 15:50:26][3] Processing: App\Jobs\SendVerificationEmail
[2018-03-26 15:50:26][...] Processing: App\Jobs\SendVerificationEmail

出了什么问题？我的SMTP设置是最新的。