I recently set up an Exchange 2013 server, as part of a migration from 2007. It appears that mail is flowing well internally and externally. However, I'm consistently getting the following error in the logs (error 1040)- "The SMTP availability of the Receive connector Default Mailbox Delivery was low (0 percent) in the last 15 minutes."
Any idea what could be the cause of this error? Is it possible that this relates to a connector that just isn't used?