postfix/dovecot imap - sent messages stay local
I've setup Postfix and Dovecot IMAP on a CentOS server. Tested it from Mac Mail and Outlook fine, but I sent different messages through the same account from each client and they both stayed in the local Sent items. I checked the settings in both clients and they are set to save sent items on the server.
Is there a setting in Postfix/Dovecot that I've possibly missed that is overriding this?
Any help is much appreciated.