Mail2 Not working, regular mail working

Hi,

Unlike some other people in this forum, the regular email function to email the website admin with the form’s contents is working just fine, but the mail2 function that sends the person submitting the form an email confirmation isn’t working, which I find odd because I believe they run on the same (or similar) systems, correct?

I tried deactivating all the other plugins to see if there was a conflict, and also installed the WP Mail SMTP plugin as instructed in the Buzztone troubleshooting documentation, but even doing a test through that plugin, it’s not working.

I also tried changing the “from” email address to see if that was an issue.

Any other ideas that might get Mail2 working? The form in question is at http://www.azrtc.com/academy-schedule/register-for-piwa/

https://wordpress.org/plugins/contact-form-7/