// This is from my config.

'EmailTransport' => [
    'default' => [
        'className' => 'Smtp',
        'host' => env('EMAIL_TRANSPORT_HOST'),
        'port' => env('EMAIL_TRANSPORT_PORT'),
        'timeout' => 30,
        'username' => env('EMAIL_TRANSPORT_USERNAME'),
        'password' => env('EMAIL_TRANSPORT_PASSWORD'),
        'client' => null,
        'tls' => true,
        'url' => env('EMAIL_TRANSPORT_DEFAULT_URL', null),
    ],
],
'Email' => [
    'default' => [
        'transport' => 'default',
        'from' => [env('EMAIL_FROM') => env('EMAIL_NAME')]
    ],
],

// Then when run Email::configTransport('default'); it gives me
[
   "path" => "file",
   "scheme" => "null",
   "className" => "null",
   "host" => "smtp.mailtrap.io",
   "port" => "25",
   "timeout" => 30,
   "username" => "9109165cf8a559",
   "password" => "a2229c0365207c",
   "client" => null,
   "tls" => true,
 ]

// Which means, when I run:
new Email('default');
// I get
InvalidArgumentException with message 'Transport class "null" not found.'