ORA-12516

ORA-12516:	TNS:listener could not find available handler with matching protocol stack
Cause:	None of the known and available service handlers for the given SERVICE_NAME support the client's protocol stack: transport, session, and presentation protocols.
Action:	Check to make sure that the service handlers (e.g. dispatchers) for the given SERVICE_NAME are registered with the listener, are accepting connections, and that they are properly configured to support the desired protocols.

[oracle@nshexdaj4db01 asmtests]$ sh test_asm.sh

SQL*Plus: Release 12.1.0.0.2 Beta on Wed May 16 01:23:40 2012

Copyright (c) 1982, 2012, Oracle.  All rights reserved.

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


Enter user-name: SP2-0306: Invalid option.
Usage: CONN[ECT] [{logon|/|proxy} [AS {SYSDBA|SYSOPER|SYSASM|SYSBACKUP|SYSDG|SYSKM}] [edition=value]]
where <logon> ::= <username>[/<password>][@<connect_identifier>]
      <proxy> ::= <proxyuser>[<username>][/<password>][@<connect_identifier>]
Enter user-name: Enter password:
ERROR:
ORA-01005: null password given; logon denied


SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus