Oracle Error ORA-12509: TNS:listener failed to redirect client to service handler

Oracle Error Message

ORA-12509: TNS:listener failed to redirect client to service handler

Reason for the Error

The dispatcher terminated unexpectedly

Solution

Attempt to connect again and if the same error occurs, contact the DBA to check the state of the dispatchers for this SID. If the problem persists, turn on tracing in the listener to determine the TNS error caused by the redirect.