Just a note. Installing Clement can stuff up your Postfix.
I was browsing the Services list and saw Clement not activated. Having an itchy finger, I activated it and got it to boot at startup.
After that, Postfix refused to start. The error log shows: Bind - Fatal: 127.0.0.1:25 Port already in use (or something to that effect). At that time, I did not know what was causing the problem. After half a day of troubleshooting, I finally found that Clement was the culprit.
To restore Postfix, you have to edit sendmail and postfix config files. Basically, delete the lines added by Clement at the end of the files.