What to do in case of "ORA-12638" error
A freshly installed Oracle database sometimes results in ORA-12638 errors. If you are running a dedicated Content Manager Oracle server, you can resolve problems by altering the SQLNET.AUTHENTICATION_SERVICES setting.
- Open Oracle file \network\admin\sqlnet.ora
- Change the value of parameter SQLNET.AUTHENTICATION_SERVICES to (none). This setting is instead of (NTS).