The amavisd daemon is apparently not running, no PID file (OSX 10.11.x)

[Roland Schmid]

Feb 11 15:13:14 ns1 postfix/smtpd[7941]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 2
Feb 11 15:13:15 ns1 postfix/smtpd[7941]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 3
Feb 11 15:13:16 ns1 postfix/smtpd[7941]: dnssd_clientstub ConnectToServer: connect() failed path:/var/run/mDNSResponder Socket:14 Err:-1 Errno:2 No such file or directory


I see these error messages in my mail.log
What does it mean?

Kind regards,
Roland