For external and internal delivery (authenticated relay)
This method allows the SMTP-enabled appliance to send messages to recipients located both inside and outside your organization.

SMTP-enabled appliance requirements:

• TLS connection (and the STARTTLS command) is supported.
• SMTP authentication is supported.
• One of the following ports is open (not blocked) in your network: 25, 465 or 587 for sending.
• Use a valid mailbox for authentication

Valid mailbox needs to have SMTP AUTH enabled.

• Open the Microsoft 365 admin center and go to Users > Active users.
• Select the user, and in the flyout that appears, click Mail.
• In the Email apps section, click Manage email apps.
• Verify the Authenticated SMTP setting by checking box next to Authenticated SMTP.

Once Authenticated STMP has been turned on you can configure you Printer, Scanner, Copier.

If your printer, scanner, or copier doesn't support modern authentication, Azure Security Defaults will block login attempts.
More information on security defaults can be found here.