Additional Information:

When I am logged into the SQL Server instance with Windows authentication I am able to retrieve data when I run my query. However, when I am logged into the instance with SQL Server authentication, I am unable to retreive data. I get the error:

"OLE DB provider "OraOLEDB.Oracle" for linked server "ORACLEBASIS2" returned message "ORA-12638: Credential retrieval failed""

Any help will be appreciated.

Thanks.