POSTFIX – How to fix “warning: mail_queue_enter: create file maildrop/XXXXXXXX: Permission denied”

Following a server crash I started receiving errors as listed. Here is how I fixed it:

service postfix stop
 killall -9 postdrop
 postfix check
 service postfix start

If ‘postfix check’ returns errors – look through them and fix them one by one then run that command again to verify if everything is OK.

If you still having problems try:

chgrp -R postdrop /var/spool/postfix/public
chgrp -R postdrop /var/spool/postfix/maildrop/
/etc/postfix/post-install upgrade-permissions
/usr/sbin/postfix set-permissions