Print and save the whole return as a pdf.
Save the return within TurboTax.
Open the pdf and look at schedule C. You're probably caught up in the "Review my Federal Return" functionality of TurboTax. Maybe looking at the pdf will help clarify what this part of TurboTax's integrity-check is complaining about. TurboTax should be giving some explanation within said integrity-check. Save a screen shot of this TurboTax integtrity-check message within TurboTax (CTRL-ALT-PRINTSCREEN). Paste that image into a word doc (CTRL-V), so maybe someone else can look at it.
These idiosyncrasies of TurboTax can be aggravating. You've answered everything as it's guided you to do, and then it throws back an invalid entry on actual IRS form in your face, that you had hoped it had handled. Get some other eyes on it, if you really get stuck. Good luck!