AMT credit carryover

Hi,

I had AMT credit carryover balance in the 2018 return (form 8801 line 26), but I missed to utilize it and did not maintain the carryover balance in the 2019 & 2020 return.  TurboTax did not ask or remind me either.  I think I can utilize this AMT credit carryover on the 2021 return.  However, TurboTax does now allow me to enter the amount on the box "Credit from AMT paid in prior years", probably because it does not see the amount on the 2020 8801 line 26.  What should I do?

 

Thank you.

Tina