Thanks @Opus 17 .
If you still live in the home, your annual payment should be on schedule 2, line 10.
Yep, it is.
If you are paying the amount the IRS expects of you (usually $250 for married filing separately or $500 for married filing jointly) then you don't need form 5405. You only need form 5405 if you are paying a different amount than the IRS expects. (It could be you are paying less, because you forgot to include the payment, or it could be you are paying more, because you sold the home and need to pay off the remaining balance.)
The letter we got says "Form 5405 is incomplete or missing from your return. Complete the form with information that supports $500.00 on line 10 of schedule 2."
Assuming that TurboTax included this $500 in our tax (we're married filing jointly), we paid it when we submitted our payment for the year (we had to pay rather than getting a return).
Look up your IRS FTHB account and see what the IRS is expecting from you.
https://www.irs.gov/credits-deductions/individuals/first-time-homebuyer-credit-account-look-up
Per this website, our "Original credit amount" is $8000 and "Total Amount of Credit Repaid Per Reported Disposition" is $500.
Then print or review your completed tax return to see what is reported on schedule 2 line 10.
It's $500 listed there.
