Not sure why you got NULL...
I get 1009.95049383621 in both 220.127.116.11 and 18.104.22.168, which definitely is not a 2D answer, although not exactly what I'd expect off the top of my head.
PS, hope to visit there someday and go to Spa...
1009.950494 corresponds to the Euclidian distance between the two points (SQRT((200-100)*(200-100)+(200-100)*(200-100)+(1000-0)*(1000-0))), so that result is correct.
I think something went wrong during the ORA10 -> ORA11 migration.
Actually, it is an Oracle 22.214.171.124 64bit database, and not an 126.96.36.199.
Did you install the Spatial extension - ORACLE Spatial ?
SELECT comp_id, control, schema, version, status, comp_name FROM dba_registry WHERE comp_id = 'SDO';