Sometimes you may encounter following error message while accessing OBIEE reports working with Oracle Database
State: HY000. Code: 10058. [NQODBC] [SQL_STATE: HY000] [nQSError: 10058] A general error has occurred. [nQSError: 17001] Oracle Error code: 1017, message: ORA-01017: invalid username/password; logon denied at OCI call OCISessionBegin. [nQSError: 17014] Could not connect to Oracle database. (HY000)
In this case try following checks
1) Where ever is BI Server from that physical server try to ping(tnsping SID) oracle database then connect to database using credentials , which you mentioned in the connection pool of RPD.
2) If above one is passed , and still you see issue same issue on the reports/in the answers then go to RPD physical layer, locate any table and try updating row count if this is failed it means connection pool settings are not correct. If row count updated properly that means your NQSConfig.INI file was not configured properly.
Make sure AUTHENTICATION_TYPE = BYPASS_NQS was commented out and restart all the services.