warning: connect to transport filter: Connection refused

I am getting the following line output in my maillog file:

Jul 7 11:34:45 mail postfix/qmgr[6623]: warning: connect to transport
filter: Connection refused

I have spent the morning trying to figure out what is wrong.

There are no references to a filter in my master.cf file or my main.cf for
postfix.

I am trying to run postfix with MailScanner.

Does anyone have any clue as to what might be causing this, and how I can
fix it.

Calling: postsuper -r ALL ends up requeing messages but it doesn't fix
the problem.

Thanks.