Backdoor IRA Conversion Confusion

I am having some trouble with Turbotax 2023 and backdoor IRA conversion. I think that I have followed the directions, however when I select that I have made and tracked non-deductible contributions to my IRA, the next screen asks for the Total Basis from form 8606. When i enter $12000 (or $11577), Turbotax replies that 'the IRA basis we transferred from 2021 is different than the basis entered. 

 

In my 2021 return, here's what i have in Form 8606"

  • line 1 = 6000
  • line 2 = 6000
  • line 3 = 12000
  • line 4 = blank
  • line 5 = 12000
  • lines 6-12 = blank
  • line 13 = 11577
  • line 14 = 423

What am i doing wrong?