cannot locate the default realm error in sql developer when creating a sys connection

I am using sql developer in that I created a ‘hr’ connection which is working fine. Now I want to work as SYS ,I tried to create a ‘sys’ connection with following values:
connection name-mysql ,username- sys as sysdba ,password-oracle, hostname-localhost ,port-1521 ,role-SYSDBA ,SID-orcl
when i test ‘it shows not find the default realm’
pls help