Using "sendmail" from Avamar

We use the replemail.sh script to report on replication status each morning.  It works fine on several of our grids.  I copied it to a newer single-node system.  The script completes successfully and I can see the replstatus.html file get created but the email is not being received from this system.  Avamar notification alert emails sent from this system do work and are being received.

I've been able to emulate sending a message via sendmail with the following code snippet (modified from replemail.sh):

(cat <
   
  
From: avamargrid@domain.com
Subject: Test Email    
To: destination@domain.com
MIME-Version: 1.0
Content-Type: text/html
Content-Disposition: inline
EOCAT
cat $html) | sendmail -f avamargrid@domain.com destination@domain.com

I can run this bit of code (after inserting the proper email addresses) from the Linux command line on our other systems and I receive a blank email (good result).  When running it from the system from which the replication report is not being received I also do not receive a test email.

Is there any configuration that is needed prior to using sendmail on an Avamar system?  I'm not a Linux expert so this very well could be something simple.  Perhaps it isn't using the correct SMTP relay?  I tried doing some Googling regarding sendmail but got lost in the differences between different distributions and how configuration is managed (definitely showing my lack of Linux knowledge here).

Thanks in advance,

Joe