SBS 2011 with Exchange 2010 and Outlook 2007/2010 clients. Out of blue users are getting emails kicked back to them from certain domains. The text below comes with the kick back.
Arrival-Date: Wed, 16 Jan 2013 23:59:36 +0000
Diagnostic-Code: smtp;400 4.4.7 Message delayed
Will-Retry-Until: Fri, 18 Jan 2013 16:59:36 -0700
Can anyone point me to log files or a place to start looking at this? THANK YOU!!!!!!