For those that are using i-MSCP on a distribution, which provide Postfix 2.10.x or newest (such as Ubuntu raring users), you must add the following SMTP restriction in the /etc/postfix/main.cf:
and then, restart postfix
Without this SMTP restriction set to an empty value, SASL authentication will not work correctly.
http://www.postfix.org/SASL_README.html#server_sasl_authz for more information.
Note1: A compatibility plugin will be provided soon for users of the 1.1.0-rc2.3 release
Note2: This issue will be fixed in 1.1.0-rc3 release.
Thank you for using i-MSCP