2019 can not be done online. so could you provide more information about what you were doing?
2019 can only be done with desktop software and can not be efiled.
https://turbotax.intuit.com/personal-taxes/past-years-products
if you do 2019 first you can transfer data from the desktop to the online a/c so 2019 information can be transferred.
see this article
https://ttlc.intuit.com/community/tax-topics/help/how-do-i-switch-from-turbotax-cd-download-to-turbo...
