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If you get that, reauthorize as the correct user, and then test again. Similarly, if you authorized as one user and need to authorize as a different user in the same session, then make sure to sign out of Microsoft first (usually this would be signing out of https://portal.microsoftonline.com). You may also want to run just this step with FlexDeploy from on Incognito or inprivate browser. Otherwise, the first user’s credentials will automatically be used with the authorization instead of prompting you to login as the second user. You will see this error when testing the email configuration:
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