Milter connection refused

When a LEAP-enabled provider receives mail, it tries to connect to the milter service, but can't connect. Milter is running: clamav 22286 0.0 0.0 476392 40 ? Ssl May30 0:04 /usr/sbin/clamav-milter --config-file=/etc/clamav/clamav-milter.conf

Jun  1 11:43:59 caribou postfix/postscreen[30675]: CONNECT from [0.0.0.0]:40969 to [0.0.0.0]:25
Jun  1 11:44:05 caribou postfix/postscreen[30675]: PASS OLD [0.0.0.0]:40969
Jun  1 11:44:06 caribou postfix/smtpd[30678]: connect from latitanza.investici.org[0.0.0.0]
Jun  1 11:44:06 caribou postfix/smtpd[30678]: warning: connect to Milter service inet:localhost:8891: Connection refused
Jun  1 11:44:07 caribou postfix/smtpd[30678]: 127C01E006C: client=latitanza.investici.org[0.0.0.0]
Jun  1 11:44:07 caribou postfix/cleanup[30681]: 127C01E006C: message-id=<574EA04A.9060704@autistici.org>
Jun  1 11:44:07 caribou postfix/qmgr[5234]: 127C01E006C: from=
Feel free to change the target version.
(from redmine: created on 2016-06-01, closed on 2016-06-07)