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NOTE: if you cannot find your service account authorization, see the documentation on setting up OAuth access and find the section on creating and authorizing the service account. Those steps will allow you to find the client ID value for your service account, which is the displayed value in this interface.
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Select the project you created when originally authorizing the G Suite IDM connector. Select "Library" on the left menu.
Search for Gmail API.
Select the Gmail API and enable the API.
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