The same VIN appears more than once in the Line 5 credits statement.
F2290-006: Form 2290, Part I, Line 5, attachment "Credits Amount Statement" [ CreditsAmountStatement], Vehicle Identification Numbers provided must not contain duplicate values.
If you filed with EasyFile2290, the rejection on your return links straight to the Credits step with this explanation, so you don't have to look the code up.
Start a fresh return here. Every return is checked against the IRS e-file schema and key IRS business rules before it is sent.
Rule text from the IRS Form 2290 Business Rules Publication (TY2026 v1.1). Explanation and fix steps are EasyFile2290's. General information, not tax advice for your situation.
Form 2290 Heavy Highway Vehicle Use Tax, figured with the IRS TY2026 rate tables (tax period July 1, 2026 – June 30, 2027).