Are you using the Online version? Online is only good for 1 return per account. But you can use the same email address for 5 accounts. Start another Online return here and sign up for a new account
https://turbotax.intuit.com/personal-taxes/online/
The Desktop program can do unlimited returns and efile 5. You can buy the Desktop CD/Download program at
TurboTax® 2021-2022 CD/Download Tax Software, Compare Desktop Tax Preparation
