550-Verification Failed

After reinstalling Discourse & using my own website host as my email provider (don’t want to use mailgun because I want to control the inbox and outbox), I’m getting 550-Verification Failed for every email. but the Email > Test button works and says ‘SENT!’ (I never get the email)

The email I used for the SMTP settings is:

jeeves@midnightexchange.com

But my error under Admin says this:

550-Verification failed for <noreply@forums.midnightexchange.com>

My next thought was just to just make an email address with my hosting provider to match, but why is it trying to use an email from the subdomain that I never specified?

Thanks for your time and reading.