PL-R-004
Error Guide

🇵🇱 PL-R-004: KSeF session token invalid in Poland

ErrorMandatoryManual Fix

KSeF API requires valid authentication token.

Quick Facts
Severity
Error (rejection)
Ruleset
ubl-2.1
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 PL-R-004

  1. 1
    Authenticate
    Use qualified certificate or trusted profile
  2. 2
    Get token
    Call InitSessionBySignature
  3. 3
    Use token
    Include in subsequent API calls

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

  • •Expired token
  • •Invalid certificate
  • •Wrong authentication method

Fix PL-R-004 automatically

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Error
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