Problems validating office 2016
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If you need multiple connectors for mail flow from Office 365 to your email server (or to a partner), make sure you validate and turn on each connector.Connector validation runs as part of the connector setup process.This article helps if you want to validate your connectors at a different time, or if you want to understand more about the process.For more information, see What happens when I change a connector that Office 365 is using for mail flow?
If you continue to have mail flow issues after validating a connector, check whether you have set up multiple connectors that might apply in a single scenario.
If you see repeated prompts to grant access to the keychain when starting an Office 2016 for Mac app, Office may have been moved to a location other than the default /Applications folder.