what seems to be the issue? there are multiple things that can cause issues. if your AGI is over $500K MFJ $250K all other filing status, the credit is not allowed. see these two threads
https://accountinginsights.org/why-am-i-not-receiving-the-illinois-property-tax-credit/#:~:text=The%...
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https://tax.illinois.gov/content/dam/soi/en/web/tax/research/publications/pubs/documents/pub-108.pdf
