Sometimes You can get ” TNS-12542: TNS:address already in use ” error.
Details of error are as follows.
TNS-12542: TNS:address already in use
To solve this error, decrease the value for TIME_WAIT state.
Or you should use of IPC protocol, If the application or failing connection is local to the Database, use IPC for connectivity, instead of TCP.
Do you want to learn more details about RMAN, then read the following articles.