Hi - I was getting the same error due to IL PIN or AGI. I essentially entered my Drivers License info in Turbotax. On the screen where it asked me to enter the AGI, i said I dont have that info. Turbotax then took me to a page to enter my IL PIN. I got the IL PIN from the https://mytax.illinois.gov/_/
I then entered that in Turbotax and submitted my returns. And finally my returns got accepted.
PS: The 2018 AGI I entered was accurate per the directions provided by Turbotax. I suspect the number IL is looking for is different than what Turbotax is suggesting, or the efiling process is buggy.
Hope this helps.
