Mine

Dec 27 11:36:25 jamesdoorcheck postfix/smtpd[6354]: fatal: open database /etc/aliases.db: No such file or directory
Dec 27 11:36:26 jamesdoorcheck postfix/master[6313]: warning: process /usr/local/libexec/postfix/smtpd pid 6354 exit status 1
Dec 27 11:36:26 jamesdoorcheck postfix/master[6313]: warning: /usr/local/libexec/postfix/smtpd: bad command startup -- throttling