Backdoor Roth IRA conversion entered caused an error.

I used backdoor Roth IRA conversion for myself and my spouse.
Followed all TurboTax instructions for CD version.
At the review stage I got the error:

IRA Contribution Worksheet: Line 15 - Amount of spouse's IRA contribution elected to make nondeductible should not be more that $(amount less than what my spouse contributed).

How to get past this step?