Intermittently, while Identity Manager is up and running, the server starts to fail with the following error in the application server log:
Listener refused the connection with the following error:
ORA-12516, TNS:listener could not find available handler with matching protocol stack
Any IM version that is using Oracle as a runtime database.
The Oracle database server (hosting the Controller database) has run out of available processes (and is therefore stopping new connections to be made to the server) Oracle database server's value for "PROCESSES" has been configured too low
Consult with your Oracle DBA to consult official Oracle documentation to confirm the best method to increase the value for PROCESSES for your Oracle environment.
Please refer to this link for further details on troubleshooting the Oracle configuration: