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Sqlplus Connection Fails with ORA-12638 (Doc ID 782419.1)

Last updated on OCTOBER 29, 2023

Applies to:

Advanced Networking Option - Version and later
z*OBSOLETE: Microsoft Windows



You are using Operating System authentication like NTS or Kerberos. While connecting to the database from sqlplus it fails with the ORA-12638.

You may connect with the following syntax

For local SYS connections,
sqlplus / as sysdba

For User connections,
sqlplus /@<alias>


sqlnet client trace shows the below SSPI error:


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