Emails
Common routes to found email logs
/var/log/maillog
/var/log/mail.log
/var/adm/maillog
/var/adm/syslog/mail.log
/var/mail/<user>
/var/log/maillog
/var/log/mail.log
/var/adm/maillog
/var/adm/syslog/mail.log
/var/mail/<user>