Hi! We deployed Exchange 2003 on both Front-End and Back-End. Back-End Exchange is our mailbox und OAB server. We hosts some customer mail domains. Each customer has its own OABs, GALs, etc. One mail domain has synchronisation problem with Exchnage server. The Outlook 2003 client of this domain get error when they send/receive messages: "The Microsoft Exchange server reported error (0x8004010F): The operation failed, an object could not be found." How can we fix this problem? Is it an access problem of Exchange Enterprise Servers or OAB rebuilding problem? Thanks in advance. Mustafa