ORA-28009: connection to sys should be as sysdba or sysoper
Cause: connect sys/
Action: Try connect sys/
ORA-28009: "connection to sys should be as sysdba or sysoper":
This occurs from Oracle 9i onwards if you try to connect as user SYS just by specifying username/password.
Instead you must connect 'as sysdba':
sqlplus "firstname.lastname@example.org as sysdba"
Note the quotes if it's on a Unix command line, which are necessary to ensure that the connection string is all one argument.