Milter crashed: can't read SMFIC_RCPT reply packet header

Applicable to:

Postfix milter is not working properly. ' /var/log/maillog ' contains the following message:

postfix/smtpd[3089]: warning: milter inet:127.0.0.1:12768: can't read SMFIC_RCPT reply packet header: Connection timed out

Incorrect milter protocol version.

Check ' milter_protocol ' version:

# postconf milter_protocol
milter_protocol = 2

Change ' milter_protocol ' value to '6' in ' /etc/postfix/main.cf ' and reload Postfix:
```
# postfix reload
```