Test Connection failed , while adding target server

Hi All,

I am trying to add target SQL server in OEM 12c with Remote monitoring,  but getting below error:

Sql server pulgin : 12.1.0.2.0

Sql server version : 11.0.300

Windows version : 2008 R2, 64 bit

Test Connection failed: [_WinAuthDLLToLoadDynamicProp;DB Credentials are found missing. DB Credentials are required for SQL based connections, MSSQL_NumClusterNodes;Can't resolve a non-optional query descriptor property [dllFile] (dllFile), _Wbem_Remote_Determination_DynamicProperty;Can't resolve a non-optional query descriptor property [dllFile] (dllFile),

I need below information , which i am confused after go through metalink ids.

1.   Under  Monitoring Database Credentials

            a. What is Database Role ? example : do i need to db_owner ?