Message Oracle RMAN-04021 - target database DBID string does not match channels DBID string

ERRORtarget database DBID string does not match channels DBID string
CAUSEThe CONNECT clause in the ALLOCATE command has resulted in a connection to a database which is not the same as the one used to connect to the target database.
ACTIONVerify that the CONNECT string connects to the same database as the one specified in the TARGET connection for the CONNECT command.