What does KSeF error 21180 mean?

The KSeF session referenced by your API call is in a state that does not permit the operation you requested — for example, trying to submit an invoice to a session that has already been closed.

Which session statuses cause 21180?

Terminal statuses like 415 (closing), 425/435 (terminated), and 445 (finished with no valid invoices). Session status 200 (open) is the only state that reliably accepts new invoice submissions.

Can I retry the same referenceNumber?

No. Once you get 21180, that referenceNumber is dead. Open a new session and retry against the new referenceNumber.

Is this error auto-fixable by Invoice Navigator?

No. 21180 is an API lifecycle error, not an XML validation error. Invoice Navigator flags it in the log so your integration can reopen the session, but the fix has to happen in the client code.

Does this affect KSeF 1.0 (test environment) or only KSeF 2.0?

The 21180 code is defined for KSeF 2.0. KSeF 1.0 uses a different error taxonomy that will be sunset in 2026.

Error codes · KSeF 2.0 · Poland

KSEF-21180Partly

KSeF session status does not allow this operation

This is the rejection, word for word: „[KSEF-21180] The KSeF 2.0 API rejected your request because the session referenced by referenceNumber is in a state that does not permit the requested action. Typical example: attempting POST /sessions/online/{ref}/invoices while the session status is 415 (closing) or an already-terminal status such as 445 (no valid invoices). The invoice itself was never processed.“

Endpoints that surface this error include POST /sessions/online/{referenceNumber}/invoices, POST /sessions/online/{referenceNumber}/close, and POST /sessions/batch/{referenceNumber}/close. The Polish message returned is "Status sesji nie pozwala na wykonanie operacji". The error payload usually includes the numeric session status. States that block invoice submission include 415 (closing initiated), 425/435 (processing terminated), and 445 (finished — no valid invoices).

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

What we doOpen a fresh session and retry. Never reuse a referenceNumber after the session has moved past status 200.

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-21180

From youThe correct figures

ThenChecked again

ProofSHA-256 and /verify link after the check

Often appears together with

KSEF-21181Sellers are not identical for all invoices in a KSeF batch KSEF-21182KSeF concurrent export limit reached PL-R-004KSeF session token invalid