Hi,
Sometimes You can get “TNS-12538: TNS:no such protocol adapter ” error.
Details of error are as follows.
TNS-12538: TNS:no such protocol adapter
Cause: The protocol adapter requested (by way of the “(PROTOCOL=..)” keyword-value pair in a TNS address) is
unknown. If the supplied address is typographically correct then the protocol adapter is not installed.
Action: Install the protocol adapter or correct typographically error, as appropriate. Note: if the supplied
address was derived from resolving the service name, check the address in the appropriate file (TNSNAMES.ORA, LISTENER.ORA or SQLNET.ORA).
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=msdbadm01)(PORT=1521))) TNS-12538: TNS:no such protocol adapter TNS-12560: TNS:protocol adapter error TNS-00508: No such protocol adapter..
To solve this error, run the relink all as follows.
$ORACLE_HOME/bin relink all
Then try to start again. It will work fine.
Sometimes you may run the lsnrctl status command with different OS user instead of Oracle, in this time you can get this error.
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/