Email Server Settings

Hello,
Until recently, I had been using Google’s SMTP for my mailing server.

I followed this tutorial, to setup Postfix + Dovecot on my Raspberry Pi.
But when going back to the server config:
Screenshot

I’ve got no clue what to enter now. I’ve tried a variety of combinations, none of which work.
Postfix and nextcloud are installed on the same machine.

I’ve tested to check weather I can actually send e-mails with:

echo "Test" | mail -s "Test" pi@domain.com

and also receiving capabilities from my Gmail account to roundcube, both work great.

From what I understand,
“From address” - Basically mean the sender, so “pi@domain.com” would work just fine.
“Auth meathod” - I’ve tired login, and used my username as “pi@domain.com” and password as the user password for pi.
“Server Address” - Really, no clue what to put here, but I’ve tied ports 587 and 465.
If anyone could chime in and guide me the the right direction, that’d be wonderful.

Ahh it seems sendmail did end up working, it just turned out that duckdns.org seems to be blacklisted by outlook, and marked as spam by most other e-mail clients.