Sending email during Import: No query results for model [App\User]

I have the following Import function:

public function collection(Collection $rows)
    {
        foreach($rows as $row)
        {
            if(User::where('email', $row['email'])->first() == null)
            {
                $user = User::create([
                    //
                'name'     => $row['name'],
                'email'    => Str::lower($row['email']), 
                'password' => Hash::make(Str::random(10)),
                ]);
                $role = $row['role'];
                $location = $row['location'];
            
                $user->roles()->attach($role);
                $user->hospital()->attach($location);
                $token = app('auth.password.broker')->createToken($user);

                Mail::to($user)->queue(new NewAccount($user, $token));
            }
            sleep(2);
        }

    }

In my local environment this works perfect. In production the email part of this loop is failing (and I know emails work, I've tested them with password resets etc.).

In Laravel Horizon it shows:

ID 111

Queue default

Tags App\User:207

Failed At 2021-03-04 15:18:16

And it gives this error:

Illuminate\Database\Eloquent\ModelNotFoundException: No query results for model [App\User]

The NewAccount Mail is:

namespace App\Mail;

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

class NewAccount extends Mailable implements ShouldQueue
{
    use Queueable, SerializesModels;

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

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return $this->markdown('emails.setpassword');
    }
}

The only difference between local and production that I can think of is the use of Redis for queue. In my local environment I'm not using Redis.

Any ideas why this may be failing? I should add that this mail class is used for normal registration and works without issue.