Just added a exchange 2010 server to a windows 2003 environment with exchange 2005. Currently exchange 2005 handles outbound email and we have a pop that handles inbound requests. Exchange 2010 has been added to the environment and we are migrating users. Users migrated to 2010 are getting error 0x80004005 and they cannot respond to outside email. I would appreciate any assistance in solving the problem with outlook 2007.