Hi,
Sometimes You can get “ORA-12640: Authentication adapter initialization failed ” error.
Details of error are as follows.
ORA-12640: Authentication adapter initialization failed
Cause: The function specified in the authentication table entry for the service failed.
Action: Enable tracing to determine the exact error.
To solve this problem, change SQLNET.AUTHENTICATION_SERVICES= (NTS) parameter to SQLNET.AUTHENTICATION_SERVICES = (NONE) on sqlnet.ora under $ORACLE_HOME/NETWORK/ADMIN directory.
The old value is as follows.
SQLNET.AUTHENTICATION_SERVICES= (NTS)
The new value should be as follows.
SQLNET.AUTHENTICATION_SERVICES= (NONE)
Do you want to learn more details about RMAN, then read the following articles.
https://ittutorial.org/rman-backup-restore-and-recovery-tutorials-for-beginners-in-the-oracle-database/