====== Maximum Message Size ====== http://wiki.zimbra.com/wiki/Configuring_maxmessagesize Check the current settings: su - zimbra zmprov gcf zimbraFileUploadMaxSize zmprov gcf zimbraMtaMaxMessageSize zmprov gcf zimbraMailContentMaxSize This sets a 40MB maximum message size (after MIME encoding): su - zimbra zmprov mcf zimbraFileUploadMaxSize 40960000 zmprov mcf zimbraMtaMaxMessageSize 40960000 zmprov mcf zimbraMailContentMaxSize 81920000 postfix reload zmcontrol restart :!: If you still have issues with maximum message size, reboot the server before troubleshooting further. FIXME Is it necessary to reload the Postfix config if you restart Zimbra?