[CentOS] Fail2ban mail failures ???

I'm using fail2ban with CentOS 6.6. Something is causing fail2ban's
alerts sent to root's mail to be rejected. Here's a clip from one of the
error messages:


        Message 48:
        From MAILER-DAEMON at lion.protogeek.org  Sun Dec 21 03:09:20 2014
        Return-Path: <MAILER-DAEMON at lion.protogeek.org>
        Date: Sun, 21 Dec 2014 03:09:19 -0600
        From: Mail Delivery Subsystem <MAILER-DAEMON at lion.protogeek.org>
        To: postmaster at lion.protogeek.org
        Content-Type: multipart/report; report-type=delivery-status;
        	boundary="sBL97EKS003880.1419152959/lion.protogeek.org"
        Subject: Postmaster notify: see transcript for details
        Auto-Submitted: auto-generated (postmaster-notification)
        Status: R
        
        Part 1:
        
        The original message was received at Tue, 16 Dec 2014 03:09:17
        -0600
        from localhost
        with id sBG97E83025627
        
           ----- The following addresses had permanent fatal errors
        -----
        <fail2ban at example.com>
        
           ----- Transcript of session follows -----
        <fail2ban at example.com>... Deferred: Connection timed out with
        example.com.
        Message could not be delivered for 5 days
        Message will be deleted from queue
        ..........
        


I used to get the messages that are now being deleted after five days.
Any suggestions?

--Doc Savage
  Fairview Heights, IL