You mean you want to pay your TurboTax fees with your federal refund but it is telling you that your refund is not enough? You are posting from Deluxe, so you can see your fees here:
https://ttlc.intuit.com/questions/2565973-how-do-i-review-my-fees-in-turbotax-online
And if you want to pay from your refund, there is also an EXTRA refund processing fee of $39.99 ($44.99 in CA) + tax which might mean your refund is not enough. You will need to pay TurboTax upfront using a credit/debit card.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**