qmail에서 아래와 같은 로그를 보았을때
퍼미션과 소유권을 확인하면 된다.

Nov 21 08:24:51 mail3 pop3d: Connection, ip=[xxx.xxx.xxx.xxx]
Nov 21 08:24:51 mail3 pop3d: chdir "/home/vpopmail/domains/domain.co.kr/lhyoung": Permission denied
Nov 21 08:26:02 mail3 qmail: 1227223562.708787 warning: unable to stat mess/19/1338481
Nov 21 08:26:53 mail3 pop3d: Connection, ip=[xxx.xxx.xxx.xxx]
Nov 21 08:26:53 mail3 pop3d: chdir "/home/vpopmail/domains/domain.co.kr/lhyoung": Permission denied
Nov 21 08:27:07 mail3 pop3d: Connection, ip=[xxx.xxx.xxx.xxx]