Email and SMTP port configuration

[phil9]

QUESTION:
We have the following system:
Mitel Small Business Edition 100
Build: 22.13.4800.0

I'm logged in the Mitel Director Connect, where do I go to setup smtp settings? Especially for voicemail.
Voicemail WAV files are not being sent to the end user.
I'm using on-premise Exchange 2019.
In the "Receive Connector", I'm allowing all devices to relay through port 25.
And yet, the user is NOT getting the an email alert for the voicemail.
In Mitel Director Connect, I go to "Administration > System > Sites"
Under Sites:
I scroll down and I see "SMTP relay server"
I type the internal IP of our Exchange 2019 server, "10.10.31.172"

Is there any Port entry and authentication I have to enter in Mitel SMTP settings? What am I missing?

[phil9]

^RESOLVED
I found the problem within the Mitel Direct Connect (Small Business Edition 100). It had nothing to do with this.
The problem was actually in the IIS 6.0 SMTP email server configuration.

When I checked this folder:
c:\inetpub\mailroot\Badmail
002c91352190812202200000026.BAD file

EMAIL ERROR MESSAGE:
From: postmaster@GBSP-vSTHQSVR-1.SanFran.local
To: MitelConnect@sanfran.com
Date: Thu, 8 Dec 2022 14:51:09 -0500
MIME-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status;
    boundary="9B095F5ADSN=_01D908BD2F4F800B00000054GBSP?VSTHQSVR?1."
X-DSNContext: 7ce717c1 - 1378 - 00000002 - C00402BF
Message-ID: <idcDjoYAP00000026@GBSP-VSTHQSVR-1.SANFRAN.local>
Subject: Delivery Status Notification (Failure)

This is a MIME-formatted message. 
Portions of this message may be unreadable without a MIME-capable mail program.

--9B095B5ADSN=_01D908BD2F4B800B00000054GBSP?VSTHQSVR?1.
Content-Type: text/plain; charset=unicode-1-1-utf-7

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.
       KathyK@sanfran.com
==
THE FIX:
I went into the Mitel windows 2012 server and checked the SMTP server configuration.
   1. Under "Administrative Tools"
   2. Open "Internet Information Services (IIS) 6.0 Manager" (older version IIS v6.0)
   NOT "Internet Information Services (IIS) Manager" (IIS v7.5). Internet Information Services 8
   3. Check the "SMTP Virtual Server" by right-clicking, and click "Properties"
   4. Click the "Delivery" tab
   5. Click "Advanced..."
   6. Check the "Smart host:" field
   7. I typed in "gbsp-exch19.sanfran.local" and it worked! Users were able to receive WAV file emails.
      NOTE: It did have mailserver.sanfran.local, which is wrong. The server was decommissioned, and was no longer available.

I did NOT have to do anything with the Mitel app or program.
==