[chrishajer]

Maybe you need a plugin to send email using an external SMTP mailer?

https://bbpress.org/plugins/topic/smtp-mailer-for-bbpress/

I’ve heard a couple times about bbPress on IIS not sending emails, but I’ve never been able to nail down why. I think people have successfully integrated SwiftMailer into bbPress as well, but that was with 0.9 or earlier. The plugin is good for 1.0+.