How do I fix KSEF-003?

Ensure continuous sequential numbering per year. This error involves a protected field — Invoice Navigator flags it in your pipeline so your team can correct it at the source.

Is KSEF-003 a critical error?

Yes, KSEF-003 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.

Can KSEF-003 be automatically fixed?

KSEF-003 involves a financial or legal field that cannot be auto-modified by policy. Invoice Navigator detects and flags this error immediately, but the correction must be made manually in your ERP or invoicing software.

Error codes · KSeF · Poland

KSEF-003Partly

Invoice number sequence gap

This is the rejection, word for word: „[KSEF-003] Invoice numbers must be sequential without gaps within each calendar year. KSeF rejects invoices with numbering gaps or duplicates.“

What to have readyThe correct figures from your bookkeeping; we show you which field is affected.

What we doEnsure continuous sequential numbering per year.

Choose the rejected invoiceor drop it here

XRechnung XML or ZUGFeRD PDF. Checking is free · corrected file €1.90 · the first every 30 days is free · no sign-up.

What the finding looks likeExample

FindingNeeds your check · KSEF-003

From youThe correct figures

ThenChecked again

ProofSHA-256 and /verify link after the check