Is there any way this could this be you?
For tax years beginning on or after January 1, 2017, the Illinois Property Tax Credit is not allowed if a taxpayer’s federal Adjusted Gross Income (AGI) exceeds $500,000 for returns with a federal filing status of married filing jointly, or $250,000 for all other returns.
If not, go back through the interview and make sure you have entered the PIN. During this process, TurboTax will tell you if you get the credit. If that is not the case, you can try to delete the state and try again.
https://ttlc.intuit.com/replies/3450510
