Oracle Message ORA-06616 - LU6.2 Driver: Attach to LU failed

ERRORLU6.2 Driver: Attach to LU failed
CAUSEThe SQL*Net LU6.2 driver was unable to attach to the LU specified in the connect string, or was unable to attach to the default LU.
ACTIONCheck that the LU name specified in the connect string, or the default LU name if no LU was specified, is correctly configured and operational.