maillog 出现错误，帮忙解释一下

mjgzln

Mar  9 12:19:33 mjgmlb postfix/pickup[13391]: warning: maildrop/7E5D4174F0: Error writing message file
Mar  9 12:19:34 mjgmlb postfix/pickup[13391]: warning: 0FD6817C2B: message has been queued for 5 days
Mar  9 12:19:34 mjgmlb postfix/pickup[13391]: 0FD6817C2B: uid=2 from=<operator>
Mar  9 12:19:34 mjgmlb postfix/cleanup[13493]: 0FD6817C2B: hold: header Received: by mjgmlb.kmip.net (Postfix, from userid 2)??id 0FD6817C2B; Sat,  4 Mar 2006 04:11:00 +0800 (CST) from local; from=<operator@mjgmlb.kmip.net>
Mar  9 12:19:34 mjgmlb postfix/cleanup[13493]: 0FD6817C2B: message-id=<20060303201100.0FD6817C2B@mjgmlb.kmip.net>
Mar  9 12:19:34 mjgmlb postfix/cleanup[13493]: warning: 0FD6817C2B: virtual_alias_maps map lookup problem for operator@mjgmlb.kmip.net