When a password string is including [@] character, Oracle backups may fail with TNS error
ORA-12154: TNS:could not resolve the connect identifier specified
ORA-12543: TNS:destination host unreachable
The logon account for the oracle database is used for that RMAN connects to a target database.
For instance, when the user name is [scott] and the password is [t@iger], RMAN will connect to the database as follows:
C:> RAMN target scott/t@iger
In this scenario, RMAN will connect to [iger] database and fail in the TNS name resolution.
If the Oracle database has OS authentication, the account for RMAN is not needed. In this scenario, RMAN will connect to the database as follows:
C:> RAMN target /
To resolve this issue please perform one of the following: