Postfix 新增使用者後, Outlook 收信發生錯誤

Postfix 新增使用者帳號後，使用Outlook收信時發生錯誤，mail log 顯示以下錯誤：

dovecot: pop3(帳號): Error: chown(/home/帳號/mail/.imap/INBOX, -1, 12(mail)) failed: Operation not permitted (egid=510(帳號), group based on /var/mail/帳號)

dovecot: pop3(帳號): Error: mkdir(/home/帳號/mail/.imap/INBOX) failed: Operation not permitted

dovecot: pop3(帳號): Error: Couldn't open INBOX: Internal error occurred. Refer to server log for more information.

dovecot: pop3(帳號): Couldn't open INBOX top=0/0, retr=0/0, del=0/0, size=0