Laravel won't use my subject line for emails - php

Question

I am trying to set a subject line for an email but Laravel keeps using the class name "FormCompleted" as the subject, here's the code I've got:
<?php
namespace App\Mail;
use Illuminate\Bus\Queueable;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Contracts\Queue\ShouldQueue;
class FormCompleted extends Mailable
{
use Queueable, SerializesModels;
protected $data;
/**
* Create a new message instance.
*
* #param $data
*/
public function __construct($data)
{
$this->data = $data;
}
/**
* Build the message.
*
* #return $this
*/
public function build()
{
return $this->subject('Form submitted')
->view('emails.form-completed')
->with('data', $this->data);
}
}
EDIT 1: The problem is only with my local server, it works on my production server

Answer 1

We may need to see the code that is used to implement the FormCompleted Mailable class and send the email, and maybe even your email Blade view as well. That would help debug further.
However, I tested out your code, and I got the email sent correctly with the appropriate subject as expected.
The only change I did was to use ->with($this->data) instead of ->with('data', $this->data); (how you have it), because, the properties defined within the $data object, are what the view uses.
public function build()
{
return $this->subject('Testing Email 2')
->view('foo.mail2')
->with($this->data);
}
I would have gotten an error otherwise (with the view trying to use unavailable properties, since the view would have been looking for a data property).