LISTENER

Check for non-successful connection attempts in listener.log

How to Purge Listener Log Data

Listener Error:

ORA-12162: TNS:net service name is incorrectly specified

ORA-12505: TNS:listener does not currently known of SID given in connect descriptor

ORA-12514: TNS:listener does not currently known of service requested in connect descriptor

ORA-12514: TNS:listener does not currently know of service requested in connect descriptor (DGMGRL)

TNS-12516 TNS:listener could not find instance with matching protocol stack

ORA-12516:TNS:listener could not find available handler with matching protocol stack

TNS-12519:TNS: no appropriate service handler found

ORA-12519:TNS: no appropriate service handler found 

ORA-12520:TNS:listener could not find available handler for requested type of server

ORA-12528: TNS:listener: all appropriate instances are blocking new connections

ORA-12528: TNS:listener: all appropriate instances are blocking new connection during connection to ASM instance remotely

ORA-12154: TNS:could not resolve the connect identifier specified

TNS-12547:TNS:lost contact, Linux Error:104: Connection reset by peer

TNS-12537:TNS:connection closed, Linux Error: 29: Illegal seek