The user account that you use to retrieve information from Yammer (the account specified by the Username parameter in the connector configuration file) must be a Yammer Verified Admin. The user must be an administrator because this is a requirement of the API used by the connector.

Be aware that the Yammer Connector will ingest all messages and all uploaded files from all groups that this user has permission to see. If your Yammer configuration permits this user to see messages in private groups, the connector will ingest those messages.