we can't see what you are doing. so this could be a Turbotax bug or you are not entering all the required info
I've provided a link to IL -ICR so you can view the form to see whats needed
note that for certain taxpayers, if there income is too high they gt no credit
https://www2.illinois.gov/rev/forms/incometax/Documents/currentyear/individual/IL-1040-Schedule-ICR....
https://www2.illinois.gov/rev/forms/incometax/Documents/currentyear/individual/IL-1040-Schedule-ICR-...
if you still have issues you'll need to contact support
