zabbix with an oracle database backend problem

[zhanghui8059]

I use zabbix oracle database backend,zabbix server can connect oracle database and no error,and zabbix web connect oracle server is not problem for install php and test connect oracle server is pass.but i input user and password in web and is not to pass,allways show 'ERROR: Login name or password is incorrect'.
I use user admin and password zabbix.why this is?pls help me.THKS!!!