Hi

On all of my Mailbox Database servers, i'm getting the following warning in my Application log: 

Level: Warning
Source: MSExchange Mid-Tier Storage 
EventID:  2009
Message:
[Process:w3wp PID:6032 Thread:89] Error occurred while resolving the Active Directory object for from email address field: 'user@externaldomain.com'. Audit log will not be generated for this case. Exception details: 
Microsoft.Exchange.Data.Storage.ObjectNotFoundException: The Active Directory user wasn't found.
   at Microsoft.Exchange.Data.Storage.ExchangePrincipalFactory.FromProxyAddress(IRecipientSession session, String proxyAddress, RemotingOptions remotingOptions)
   at Microsoft.Exchange.Data.Storage.ExchangePrincipalFactory.FromProxyAddress(ADSessionSettings adSettings, String proxyAddress, RemotingOptions remotingOptions)
   at Microsoft.Exchange.Data.Storage.ExchangePrincipal.FromProxyAddress(ADSessionSettings adSettings, String proxyAddress)
   at Microsoft.Exchange.Data.Storage.COWAudit.GetSubmitEffectiveMailboxOwner(MailboxSession session, CallbackContext callbackContext)

I have three Exchange Server 2013 MBX/CAS servers, and two Exchange Server 2013 Edge Transport servers in front of them.

As mentioned earlier, this warning is on all three of the MBX/CAS servers. The external e-mail address vary.

I've used the Get-MessageTrackingLog to debug, and I can see that this error comes when an internal user sends a "Meeting Forward Notification" to an external e-mail address. Exchange tries to resolve the external e-mail address in Active Directory and throws this warning, for some reason.

Is there anyone that knows how to fix this?

• Edited by Smoer40 Friday, January 30, 2015 1:07 PM

Hi Smoer,

According to your description, I understand that Exchange server get a warning Microsoft.Exchange.Data.Storage.ObjectNotFoundException: The Active Directory user wasn't found when internal user send a message to an external e-mail address.
If I misunderstand your concern, please do not hesitate to let me know.

I want to double confirm some question, please help to collect answers for following questions:
1. Is it deliver successful which message send with this warning?
2. Is there any send connector used for this internal user?

By the way, please pay attention to Message from internal senders section in Mail flow for Exchange 2013, for your reference:
https://technet.microsoft.com/en-us/library/aa996349(v=exchg.150).aspx

Best Regards,
Allen Wang