SSMS Linked Server -ORA-28009: connection as SYS should be as SYSDBA or SYSOPER (Microsoft SQL Server, Error: 7303)

How could I use "Linked Server" from SSMS IDE to connect the Oracle server database with "SYSDBA"? I've tried many methods as following to show you what I did right now: Oracle client connect to Oracle Server data: SSMS connect to Oracle Server data: More testing information I also use "SQLPLUS" to check *tnsnames.ora* the file is okay or not but the answer is as following 1. sqlplus SYS/Oradoc_db1@DBNAME as SYSDBA <-- is okay 2. sqlplus SYS/Oradoc_db1@DBNAME <-- Error