Cannot save sent message or Postfix permission problems.

I started getting a “couldn’t save sent message” error message in thunderbird.

I logged onto the server and restarted courier-imapd and postfix and retried. Still the same error.

I checked the maillog and found this error.

Mar 12 17:33:53 plesk postfix/postfix-script[21448]: warning: not set-gid or not owner+group+world executable: /usr/sbin/postdrop

As usual, a quick run of the command

postfix check

Confirmed it was a problem,

So I ran the fix permissions command.

postfix set-permissions

Apparently this is not a well known command so I have posted here.