If you receive this message after migrate users to SmarterMail: System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it 127.0.0.1:17001 goto smartermail domains folder and delete all migrated domains. goto Service directory, edit domainList.xml and remove all migrated domain entries. restart the SmarterMail service login and create a domain without any