No. Online is only for 2020 returns. How did you file the original 2019 return? If you used Turbo Tax online you need to amend using the Desktop program installed on a full Windows or Mac computer.
Amend 2019
https://ttlc.intuit.com/community/amending/help/how-do-i-amend-my-turbotax-online-return/00/27577
