KSEF-21178
Error Guide
🇵🇱 KSEF-21178: KSeF UPO (Urzędowe Poświadczenie Odbioru) not found in Poland
ErrorMandatoryManual Fix
You requested the UPO (Urzędowe Poświadczenie Odbioru — the official acceptance confirmation) for a KSeF invoice, but the system could not find a UPO matching the provided criteria. Either the invoice has not yet been assigned a UPO, or the search parameters (referenceNumber, KSeF number, sessionReferenceNumber) do not identify a valid invoice.
Quick Facts
Severity
Error (rejection)
Ruleset
KSeF 2.0
Fix Confidence
0%
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(3) rules for Poland.
How to Fix KSEF-21178
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Poland E-Invoicing Requirements
Phase
Status
Scope
KSeF voluntary
Live (Jan 2022)
All VAT payers (opt-in)
B2B mandatory — Phase 1
Live (Feb 1, 2026)
Large taxpayers (>200M PLN turnover)
B2B mandatory — Phase 2
Live (Apr 1, 2026)
All remaining VAT-registered entities (SMEs, sole proprietors, VAT-exempt businesses)
B2G
Live (Feb 1, 2026)
Included in general KSeF mandate
Financial penalties
Jan 1, 2027
Up to 100% of VAT amount on non-compliant invoices
Common Causes
- •Polling for UPO before the invoice has been fully processed
- •Wrong KSeF number passed — often confusing invoice reference with KSeF number
- •Missing permissions on the technical user requesting the UPO
- •Batch session not yet closed
- •Invoice was rejected — UPO is never issued for rejected invoices
Fix KSEF-21178 automatically
Upload your invoice and let Invoice Navigator auto-remediate this error.