I’m not certain what you mean by that, but that looks to not be part of the recommended standard install process, why don’t you use that?
We strongly recommend using a dedicated email service. Email server setup and maintenance is very difficult even for experienced system administrators, and getting any part of the complex required email setup wrong means your email won’t be delivered, or worse, delivered erratically.
For what it is worth, my forum was set up to use Mailgun several years ago, and it has just worked ever since, without skipping a beat. I don’t remember much about the setup process now, but I don’t believe it was very difficult. E-mail deliverability and reputation score has remained very high.