Hi,
Sometimes You can get “ORA-12569: TNS:packet checksum failure ” error.
Details of error are as follows.
ORA-12569: TNS:packet checksum failure
Cause: The data received is not the same as the data sent.
Action: Attempt the transaction again. If the error is persistent, turn on tracing and reexecute the operation.
This error may be related with the Firewall settings.
Change the firewall so that features that would change / alter a packet such as Deep Packet Inspection (DPI), are not enabled.
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/