I get the following error everytime the Mailbox Assistant Service runs and it logs a 2161 Event in the App log. Under CN=Addressing,CN=Address-Templates,CN=409 there are 4 objects that produce this error. Faxroute,Numeric,Octelan and UMAVA. None of these objects have LegacyDN's set. Is this something that needs to be added.

 MSExchangeMailboxAssistants.exe (MSExchMbxAsst)   3116
   CN=FAXROUTE,CN=409,CN=Address-Templates,CN=Addressing,CN=First Organization,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=com
   DC01.Domain.com
   ExchangeLegacyDN
   You must provide a value for this property.

Are these legacy leftover objects from a previously instaled fax server?  If so, and you don't use it anymore, you should be able to remove these using ADSI Edit.

Hi,

If these objects are not useful, we can follow Ed's suggestion to remove it from ADSIEdit.

If it is still in using, we can add X500 address for these objects to have a try. If all above suggestion doesn't work, please provide more detailed information about event logs and Exchange configurations for further analysis.

Regards,