For the past several days we have been getting this particular event multiple times every couple minutes on all of our hub Exchange 2007 sp1 with rollup 2 servers: -------------------------- Event Type:ErrorEvent Source:MSExchangeTransportEvent Category:SmtpReceive Event ID:1025Date:7/30/2008Time:7:54:34 AMUser:N/AComputer:CHQPVUW1162Description:SMTP rejected a (P1) mail from 'ADdomain/RicksGR@ldschurch.org' with 'Client CHQPVUW1162' connector and the user authenticated as 'ADdomain\RicksGR'. The Active Directory lookup for the sender address returned validation errors. Microsoft.Exchange.Data.ProviderError For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.-------------------------- Every instance is the same user and occurs throughout the day and night, apparently even when this user is not logged on to Exchange. Research I've done so far about this event indicates that it can occur when a user tries to send as a different user without the appropriate "send as" rights, but due to the enormous number of events (tens of thousands per hub server over the past few days), this explanation doesn't seem to fit unless the client is caught in some sort of loop. Any thoughts would be appreciated. Aaron

Hi, Firstly, I need your help to clarify the following questions: 1, Did you try to send the email by using the RicksGR account? 2, What type of client for the RicksGR account? OE or Outlook? 3, Could you send the email normally without any issue except for coming up the message in the event log? 4, Have you changed any configuration on the Client CHQPVUW1162 connector or the client side? In order to obtain more value information on the troubleshooting way, please enable the Protocol logging level to Verbose of Client CHQPVUW1162 connector. Then test to send one email and locate the location of the log, paste the information to the forum. Thanks Allen