Laravel 5 Error 500 when sending mail via smtp

I wanted to make a simple contact form on my Website, where the user get's a confirmation mail and I get the text, the user sent me. But somehow it doesn't work and I don't know why.

ContactController:

    public function sendMail(Request $request){

    $this->validate($request, [
        'email' => 'required|email',
        'name' => 'required',
        'subject' => 'required',
        'text' => 'min:10 | max:65536'
    ]);

    $data = [
        'email' => $request->input('email'),
        'name' => $request->input('name'),
        'subject' => $request->input('subject'),
        'text' => $request->input('text')
    ];

    Mail::to($request->input('email'))->send(new RequestReceived($data));
    Mail::to('test@velocityvideogroup.com')->send(new ContactEmail($data));

    $request->session()->flash('success', 'Request has been successfully sent!');
    return redirect('/contact');
}
}

MailClasses:

ConfirmationMail:

class RequestReceived extends Mailable{

use Queueable, SerializesModels;


protected $data;
/**
 * Create a new message instance.
 *
 * @return void-
 */
public function __construct($data)
{
    $this->data = $data;
}

/**
 * Build the message.
 *
 * @return $this
 */
public function build()
{
    return $this->markdown('emails.received')
                ->subject('Velocity | Request received!')
                ->with([
                    'name' => $this->data['name'],
                    'text' => $this->data['text']
                ]);
    }
}

Mail I should get:

class ContactEmail extends Mailable
{
use Queueable, SerializesModels;

protected $data;
/**
 * Create a new message instance.
 *
 * @return void
 */
public function __construct($data)
{
    $this->data = $data;
}

/**
 * Build the message.
 *
 * @return $this
 */
public function build()
{
    return $this->markdown('emails.contactemail')
                ->from($this->data['email'])
                ->subject($this->data['subject'])
                ->with([
                    'name' => $this->data['name'],
                    'text' => $this->data['text']
                ]);
    }
}

.env file:

MAIL_DRIVER=smtp
MAIL_HOST=send.one.com
MAIL_PORT=465
MAIL_USERNAME=test@velocityvideogroup.com
MAIL_PASSWORD=*************
MAIL_ENCRYPTION=tls

MAIL_FROM_ADDRESS=test@velocityvideogroup.com
MAIL_FROM_Name=Test

via Sebi