Connection to sys should be as sysdba or sysoper
ORA-28010 – Oracle Error Code
Cannot expire external or global accounts
ORA-28011 – Oracle Error Code
The account will expire soon; change your password now
ORA-28020 – Oracle Error Code
IDENTIFIED GLOBALLY already specified
ORA-28021 – Oracle Error Code
Cannot grant global roles
ORA-28022 – Oracle Error Code
Cannot grant external roles to global user or role
ORA-28023 – Oracle Error Code
Must revoke grants of this role to other user(s) first
ORA-28024 – Oracle Error Code
Must revoke grants of external roles to this role/user
ORA-28025 – Oracle Error Code
Missing or null external name
ORA-28026 – Oracle Error Code
User with same external name already exists