Error – postfix/smtpd[xxxx]: warning: SASL authentication failure: cannot connect to saslauthd server: Permission denied
Solution :
If Postfix is looking at /var/run/saslauthd, to see the files in /var/spool/postfix/var/run/saslauthd , make a symlink :
# ln -s /var/spool/postfix/var/run/saslauthd /var/run/saslauthd
After that, restart the services :
# service saslauthd restart
# service postfix restart