RMAN-06820: WARNING: failed to archive current log at primary database

Trying to backup the database but getting an error

RMAN-06820: WARNING: failed to archive current log at primary database

When looked deeper in by looking at the rman logs, it was noticed that I was getting an invalid username and password.

RMAN-06820: WARNING: failed to archive current log at primary database
ORACLE error from target database:
ORA-17629: Cannot connect to the remote database server
ORA-17627: ORA-01017: invalid username/password; logon denied
ORA-17629: Cannot connect to the remote database server

Reason:

This happens because the user trying to perform the backup which is rman in this case does not have sysdba permission

Because of lacking sysdba permission this user does not have entry in password file and can be checked under

select * from v$pwfile_users;

Solution:

It is simple, just grant sysdba to rman and it will fix the issue.

Please note that I know we should grant sysbackup to rman rather than sysdba

It is addressed in another post.