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: unchecked = disabled, checked = enabled.
When you're finished, click Save changes.
Use the Microsoft 365 admin center to enable or disable SMTP AUTH on specific mailboxes Print
Modified on: Sun, 12 Feb, 2023 at 4:18 PM
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