Check Bulb wont turn off

Hi i am using 2000 hyhundai Elantra. few months back i got check engine light. so we scan and change the Oxygen Map sensor then again check light came. then we scan again and told to replace Oxygen sensor located in exhaust line .
but after driving few KM check light came again. now the error shows as Catalyst converter issue.

Please help me

A lot of times a converter causes a O2 sensor code. An air leak can also cause a code.