The program is pretty smart and it may be aware of income that you forgot. Remember household income is not the same as taxable income. Adding back passive losses, nontaxable pension, etc can add up to make you ineligible.
Form M1PR instructions. pages 8 and 9, has a list of household income that is added to your income even though is it nontaxable income. You may have some in the program that the computer knows about which makes you ineligible.