Exchange 2010 – Distribution group does not receive external emails Posted by alambert on March 14, 2016 Posted in: Exchange. Leave a Comment Mail Flow Settings tab>Message Delivery Restrictions>Properties, uncheck “Require that all senders are authenticated”, and click OK Posts navigation ← Remove Spam by Subject / From – Powershell Script – Exchange 2010 Exchange 2010 – Delete a user’s mailbox content with powershell →