用户名和密码都是对的，为什么会出现output_db.c:110 output_db write error:Connection refused？

[root@localhost cron.d]# tsar --cron
[Wed Dec 12 11:12:33 2018] output_db.c:110 output_db write error:Connection refused

开启采集以后，提示无法连接数据库。
tsar2db的配置如下：
[root@localhost cron.d]# cat /etc/tsar2db/tsar2db.cfg
#mysql database hostname or ip
db_address=localhost
#database port default is 3306
db_port=3306
#mysql user info for tsar
db_name=tsar
db_user=root
db_pw=11
#tsar2db port.same as output_nagios_addr at /etc/tsar/tsar.conf
server_port=56677
#log for tsar2db.see more@/var/log/message
debug=0
pid_file=/var/run/tsar2db.pid
配置中用户名和密码都是正确的。请问这是什么问题？或是哪里有详细的错误日志？

Start with the tsar --cron failure and the output_db.c:110 message, then inspect /etc/tsar2db/tsar2db.cfg and the /var/log/message log mentioned in the report. Check the configured database and server ports and determine why the database connection is refused. Done means identifying the cause and documenting the relevant error details or configuration fix.

Written by the indexing model from the issue text.