The issue isn’t with postgrey or postfix, but with milter-greylist.
What you may want to do is edit /etc/postfix/main.cf, and comment out the lines beginning with “smtpd_milters” and “non_smtpd_milters”. After that, restart Postfix.
not working,,,, hummm 😉
NOTE: http://unix.stackexchange.com/questions/74477/postfix-smtpd-warning-connect-to-milter-service-unix-var-run-opendkim-opendki
warning: connect to Milter service local:/run/milter-greylist/milter-greylist.sock: Connection refused