mails in var/spool/mqueue/

in my slackware 12 box, i can see many mails in var/spool/mqueue/ but
when i send mail, i get message as below . Are my mail already sent? My
linux box only failed to send out email since yesterday. Was OK before
this. May i know where should I troubleshoot?

Dec 4 00:24:50 host_node_name sm-mta[4448]: lB3GOnMR004448:
from=, size=706, class=0, nrcpts=1,
msgid=<7957089.41196699090185.JavaMail.tomcat@host_node_name>,
proto=ESMTP, daemon=MTA, relay=host_node_name.host.com [192.168.1.123]
Dec 4 00:24:50 host_node_name sm-mta[4448]: lB3GOnMS004448:
from=, size=705, class=0, nrcpts=1,
msgid=<24002253.51196699090519.JavaMail.tomcat@host_node_name>,
proto=ESMTP, daemon=MTA, relay=host_node_name.host.com [192.168.1.123]