cant send mails anymore

after the installation of mail scanner (i think so) there is the following error if i try to send mails out of my server

Sep 30 08:24:54 mail postfix/submission/smtpd[5254]: connect from 178-175-1**-.static.as49.net[178.175.1*.**]
Sep 30 08:24:55 mail postfix/submission/smtpd[5254]: warning: SASL: Connect to private/auth failed: Connection refused
Sep 30 08:24:55 mail postfix/submission/smtpd[5254]: fatal: no SASL authentication mechanisms
Sep 30 08:24:56 mail postfix/master[4905]: warning: process /usr/libexec/postfix/smtpd pid 5254 exit status 1
Sep 30 08:24:56 mail postfix/master[4905]: warning: /usr/libexec/postfix/smtpd: bad command startup – throttling

is there anybody out there who can help me?