Installment sales

2023, we sold a business and had the first installment sale. 2024, we received a second payment of the same sale. I'd like to set up form 6252 the same way as last year, but it's not working. It comes up with "based on the information entered, you have no installment sale income..." How do I enter this correctly?

We don't have the business any longer so there's no Sch C if that matters.

I entered:

Principal payments received (2023) 2500, and then entered 2500 for 2024. Then, get the above message.

Thanks for your help.

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