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Next, go to System Settings → Email Settings - Outgoing Email Settings, and select OAuth for the Auth Type.
If you want to send as a shared mailbox, assign a password to the shared mailbox, and login as that user to authorize. You don’t need to assign a license to do that. Open an incognito window. Login to outlook.office.com as the shared mailbox or desired account. It is ok to get a 500 error about needing a license. No license is needed.
User Name - This must match the user who completed the Authorize action for Microsoft Azure application on the System Settings - Integration Settings page. This user name will be used for Microsoft Graph API.
OAuth Application - Choose the OAuth application you just created.
From Address - The user must have permission If you want to send from this address, or it won’t work. This can be a shared mailboxa different mailbox than they one you used to authorize.
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Incoming Email Settings
If you are using the same user for outgoing and incoming emails (recommended) then you can leave the top of the section titled Incoming Email Settings mostly blank. Follow notes provided on Description of each setting.
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