No hint path defined for [mail] Laravel 5.4

You need to call the markdown() method in the build() method of your mailable - not the view() method. See the example below:

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

To use Markdown mailable messages, you have to update the build method of your Mailable class and instead of view(), you have to use markdown().

Like this:

public function build()
{
    return $this->markdown('emails.registered');
}