If it doesn't let you clear and you haven't paid or filed you could just start a new account. Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version.
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...
Where is your 2019 return to transfer? Is it in an Online Account or on your computer? Hmmmm, starting a new account won't let you transfer if 2019 is in a different online account. You might have to do 2020 without transferring from 2019. Unless you can download the .tax2019 file to your computer, then you might be able to transfer it into a new online account.
