IL1040-8200-1 - "The Primary Taxpayer Drivers License number or State ID number did not match the Drivers License or State ID number on the Illinois Department of Revenue production file. If PC Online return, at least one of the following Primary Taxpayer signature fields must be present and match the department production file: Primary IL-Pin, Primary Prior Year AGI, or Primary IL Shared Secrets Drivers License/State ID Number."
It must be an Illinois DL or state ID if that's what you are using
Don't enter from memory
if that doesn't work, try the prior year's AGI unless you filed late then try zero
also if you are not a first-time Illinois filer check your IL-PIN
IL-PIN inquiry
if none of this works, you'll have to file by mail, though you should still be able or already have e-filed Federal