What is the logic for emails in Discourse notifications on Cloudron?

[andxclfor]

I think I got it with changing the root email.

But I am unsure how to configure the Discourse notification mail addresses.

I am getting error:

550 Authenticated user connect.app@root-domain.de cannot send mail as discourseadmin+verp-9cf967b0413a4792c2e2aec8cdbb7805@rootdomain.de

There are quite a few settings under: /admin/site_settings/category/email
Is there a guide what to set how?