Client connections may intermittently fail with either of the following errors:
TNS-12516 TNS:listener could not find instance with matching protocol stack
TNS-12519 TNS:no appropriate service handler found Additionally, a TNS-12520 error may appear in the listener log.
TNS:listener could not find available handler for requested type of server The output of the lsnrctl services command may show that the service handler is in a "blocked" state.
e.g. '"DEDICATED" established:1 refused:0 state:blocked'
Fix
Increase the value for PROCESSES.
read metalink note :240710.1
