Reject Code IL1040-8100-1 How to fix this code on the state

regi408 — Wed, 22 Apr 2026 22:16:06 GMT

Re: Reject Code IL1040-8100-1 How to fix this code on the state

Rosan100 — Wed, 22 Apr 2026 22:55:43 GMT

Verify AGI: Check your 2024 tax return and ensure the prior year AGI matches the 2024 return.
( Adjusted Gross Income-AGI is found on Line 11 of Form 1040)
Use IL-PIN over AGI: If you have an 8-digit IL-PIN, use it instead of the prior year AGI to sign your return,
To obtain an Illinois Department of Revenue (IDOR) IL-PIN for individual income taxes, use the IL-PIN Inquiry tool on MyTax Illinois . The IL-PIN is typically assigned automatically after processing your first Illinois income tax return (IL-1040)