KSEF-003
Error Guide
🇵🇱 KSEF-003: Invoice number sequence gap in Poland
ErrorMandatoryManual Fix
Invoice numbers must be sequential without gaps within each calendar year. KSeF rejects invoices with numbering gaps or duplicates.
Quick Facts
Severity
Error (rejection)
Ruleset
KSeF
Mandate
B2B Mandatory
Fix Type
Manual
Why This Matters in Poland
Poland requires e-invoicing using KSeF XML format. Invoices with this error will be rejected. They cannot be processed for Poland compliance.
Invoice Navigator covers 134 KSeF FA(2) rules for Poland. Auto-remediates 78% of top rejection errors.
How to Fix KSEF-003
Poland E-Invoicing Requirements
Phase
Status
Scope
KSeF voluntary
Live (Jan 2022)
All VAT payers (opt-in)
B2B mandatory
Live (Feb 2026)
All Polish VAT payers
B2G
Live (Feb 2026)
Included in general KSeF mandate
Common Causes
- •Multiple systems using same number series
- •Cancelled invoices leaving gaps
- •Database restore issues
Fix KSEF-003 automatically
Upload your invoice and let Invoice Navigator auto-remediate this error.