Nondeductible IRA Contribution limit

I am entering a Backdoor Roth.  I have entered info from my 1099R and the traditional nondeductible IRA contribution (same amount = $7,000).  I do not have an employer sponsored retirement plan and am over 55.  I keep getting a notice that the IRA worksheet is showing that my IRA nondeductible limit is $5,030.  Any idea why?