ORA-12560: TNS:protocol adapter error | connecting as SYS user

Experts -

I'm getting the following error when connecting using windows SQLPLUS command line.

Connected to:
Oracle Database 11g Enterprise Edition Release - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options

  2  /


SQL> show user;
SQL> def
DEFINE _DATE           = "15-JUL-15" (CHAR)
DEFINE _USER           = "SYSTEM" (CHAR)
DEFINE _EDITOR         = "Notepad" (CHAR)
DEFINE _O_VERSION      = "Oracle Database 11g Enterprise Edition Release - 64bit Producti
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options" (CHAR)
DEFINE _O_RELEASE      = "1102000400" (CHAR)
SQL> conn sys / as sysdba
Enter password: *********
ORA-12560: TNS:protocol adapter error

Warning: You are no longer connected to ORACLE.

I can be able to connect as system but not as SYS.

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johnsoneSenior Oracle DBACommented:
The command should be

conn / as sysdba


conn sys as sysdba
slightwv (䄆 Netminder) Commented:
You don't show the connect string/process when you connected as system.
adding to johnsone  comments

command should be

connect sys/<syspassword>@<your tnsnames> as sysdba
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slightwv (䄆 Netminder) Commented:
The @tnsnames is not necessary if you are on the database server.
johnsoneSenior Oracle DBACommented:
Based on original post connect strings, my guess is the tnsname is not required in the connect string.

I also highly recommend against putting the password in the connect string like that.  Let SQL*Plus prompt for it.  Having a clear text password on your screen is a security risk.

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sventhanAuthor Commented:
Thanks for the help.
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