Getting undefined property error exception when changing mail::send to mail::queue in laravel 8

Here is code that works:

Mail::to($emails)->send(new ExceptionOccurred($e));

And then I change it to:

Mail::to($emails)->queue(new ExceptionOccurred($e));

When I do I get the error:

ErrorException: Undefined property: App\Mail\ExceptionOccurred::$content in C:\inetpub\wwwroot\laravel\app\Mail\ExceptionOccurred.php:33

This is ExceptionOccurred.php:

namespace App\Mail;

use Illuminate\Bus\Queueable;
// use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;

class ExceptionOccurred extends Mailable
{
    use Queueable, SerializesModels;

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

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->markdown('mail.ExceptionOccurred')
            ->subject('Exception on live instance')
            ->with('content', $this->content);
    }
}

This is the relevant portion of the exception handler:

if ( $exception instanceof Exception ) {
    $e = FlattenException::create($exception);
} else {
    $e = $exception;
}

$emails = json_decode( env('MAINTAINER_EMAILS') );

if (app()->environment('production') || app()->environment('testing') ) {
    Mail::to($emails)->send(new ExceptionOccurred($e));
}

To re-iterate, Mail::send() works, but Mail::queue() does not. I believe the queue is set up correctly.

You have to define the content attribute before the construct, like this:

namespace App\Mail;

use Illuminate\Bus\Queueable;
// use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;

class ExceptionOccurred extends Mailable
{
    use Queueable, SerializesModels;
 
    public $content;

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

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->markdown('mail.ExceptionOccurred')
            ->subject('Exception on live instance')
            ->with('content', $this->content);
    }
}

Reference: https://laravel.com/docs/8.x/mail#view-data