Hey Debasmitha! According to the rules set by NTA. "A candidate can appear JEE Advanced for a maximum of two times in consecutive years". If you have appeared for your Boards in 2019, you have chances to attempt only in 2019 and 2020, no matter if you have failed to attempt in 2019. Hence, you cannot appear for JEE Advanced in 2021. Don't panic, you'll get admitted to a good college. There are so many options you can choose. If you want to know the college you are eligible to get admission, use the link below:

https://engineering.careers360.com/jee-main-college-predictor

Hope this helped!