Illinois taxation

as stated the income/loss shown on the federal return for each of those years should be the same for the years 2021-2023. something was done wrong for Illinois in 2021 and 2022.

example when you completed Illinois schedule NR say for 2022 did you report the federal income/loss in column B on line 15. 

however, if you treated this as business and you had business income outside of Illinois the computation for column B is more complicated

then you used the business apportionment worksheet

which would be Illinois rent divided by gross business income everywhere (reported on line 15) times the amount on line 15 column A of schedule NR 

not sure what you did for 2021 or 2022 but it seems like would paid taxes were there was no income 

review schedule NR