Hi,
Sometimes You can get ” ORA-12542: TNS:address already in use ” error.
Details of error are as follows.
ORA-12542: TNS:address already in use Cause: Specified listener address is already being used. Action: Start your listener with a unique address. ns main err code: 12542 TNS-12542: TNS:address already in use ns secondary err code: 12560 nt main err code: 512 TNS-00512: Address already in use nt secondary err code: 48 nt OS err code: 0
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 Oracle Database for Beginners, then read the following articles.
https://ittutorial.org/oracle-database-19c-tutorials-for-beginners/