How to Check Whether KSeF Is Experiencing an Outage

You click send, but KSeF does not respond. Before treating this as a system outage, establish where the problem lies: with the Polish Ministry of Finance, such as an outage, unavailability or maintenance, or on your side, such as the internet connection, certificate, permissions or incorrect FA(3) XML data. The diagnosis determines how you issue invoices and when you must submit them.

The official sources of truth are Polish Ministry of Finance announcements and the public Latarnia KSeF status API. KSeFGPT provides a public status monitor at ksefgpt.pl/en/status, which retrieves data directly from the Ministry's Latarnia KSeF feed and refreshes it automatically every 60 seconds.

The submission deadline depends on the system state. After announced unavailability, submit no later than the next business day under Article 106nh of the Polish VAT Act. After an outage, you have 7 business days under Article 106nf. During a total outage, invoices are not subsequently submitted to KSeF. For an ordinary connection problem on your side, use offline24 mode under Article 106nda.

To check whether KSeF is experiencing an outage, open the KSeFGPT status monitor or query the Polish Ministry of Finance's public Latarnia KSeF API. If the status is Failure or Total failure, the problem is on the Ministry's side. If it is Available, check your internet connection, certificate and permissions.

Use this order for a quick diagnosis:

1. Check the public system status. The KSeFGPT monitor at /en/status shows the current status of the production KSeF system using Ministry data.

2. Check the Ministry's technical announcements. This is where maintenance, unavailability and outage notices are published.

3. Rule out a problem on your side. Check the internet connection, certificate validity, permission to issue invoices and the correctness of the XML data.

This is the most important distinction in the diagnosis. A Ministry-side outage affects all taxpayers at the same time: Latarnia KSeF reports an outage, a technical announcement appears and errors occur regardless of the software used to send invoices. A local problem affects only you: the Ministry status is Available while other users can submit invoices normally.

Do not confuse a technical HTTP failure, such as a timeout or a 5xx response, with the legal status of an outage. One failed request is not yet a KSeF outage under the Polish VAT Act. The Ministry of Finance must officially announce an outage. Only that announcement activates the offline procedure with a 7-business-day submission deadline.

The table covers the most common symptoms and shows where to look for the cause.

The primary source is the Ministry's KSeF technical announcements. The Polish Ministry of Finance publishes maintenance, unavailability and outage information there. Maintenance is announced in advance, while outages are announced after they are identified. A total outage is additionally announced through mass media.

The Ministry's public Latarnia KSeF API at api-latarnia.ksef.mf.gov.pl provides the current system status. External status services, including the KSeFGPT monitor, use this source. General updates appear in KSeF News. For individual matters, the KSeF helpline can be reached at +48 22 330 03 30.

Do not base the diagnosis only on social media. User reports describe symptoms, but only official Ministry announcements determine the legal outage status and the invoice submission deadline that follows from it.

KSeFGPT provides a public KSeF status monitor at ksefgpt.pl/en/status. It shows one current status for the production KSeF system and retrieves the data directly from the Polish Ministry of Finance's public Latarnia KSeF API, without altering or delaying the information.

The page refreshes the status automatically every 60 seconds, includes a manual refresh button and displays the time of the latest update. It distinguishes four system states: Available, Scheduled maintenance, Failure and Total failure. If the data cannot be retrieved, it shows an unknown state. Below the status, you can see active Ministry notices about outages, planned maintenance and restored availability.

The monitor is public and does not require an account. It shows the current state and active Ministry notices, but it does not provide uptime history or historical statistics. Bookmark it if you need one place to check whether an invoice submission problem is on the Ministry's side.

For an application user, an outage usually means that submission fails or never finishes, the document does not receive a KSeF number, and no UPO, the official acknowledgement, appears despite a correctly prepared file. For an integrator, the symptoms include connection timeouts, 5xx responses from the KSeF gateway and sessions that do not reach a final state.

Watch out for false alarms. Invoice status 100, accepted for further processing, and status 150, processing in progress, are normal transitional states rather than signs of an outage. Larger document batches may take time to process. A missing UPO also does not always mean a system problem: the document may still be processing or may have been rejected with a specific error code.

Before declaring an outage, check the status of the same invoice and session. See How to check an invoice status in KSeF after submission and Missing UPO in KSeF. If the document was rejected with an error code, read Invoice rejected by KSeF.

Polish regulations distinguish several system states, each with a different working procedure and invoice submission deadline. Announced unavailability, including maintenance, is published in advance in the Ministry's Public Information Bulletin. An outage is unplanned and announced in the Bulletin and official communications. A total outage is an exceptional state announced through mass media.

The table also includes offline24, which is not a system state. It is a voluntary choice available to a taxpayer when a local problem, such as loss of internet access, occurs while KSeF itself is working normally.

If the Ministry status and announcements confirm an outage or unavailability, switch to offline mode. You still prepare a structured invoice: the issue date is taken from the P_1 field in the FA(3) XML file, and the buyer receives a visualisation with QR codes. Correct offline markings require a KSeF certificate, so obtain one before an outage rather than applying for it while the system is unavailable.

Keep a simple list of invoices issued during the outage or unavailability and track the time remaining for submission. After the Ministry announces the end of an outage, you have 7 business days under Article 106nf of the Polish VAT Act. After announced unavailability, submit no later than the next business day under Article 106nh. Late submission may have consequences under Poland's fiscal penal rules, so do not treat the full deadline as spare time.

Before sending the same invoice again during system problems, check the status of the original session. If the first submission did reach KSeF, another attempt after service is restored will return duplicate error 440 and make the audit trail harder to follow.

If the problem is on your side and KSeF is working, restore the connection, certificate or permissions and submit the invoice online. If the fix takes longer, use offline24 and submit without delay, no later than the next business day after issue. See How long do you have to send an invoice to KSeF? for all deadlines covering online submission, offline24, unavailability and outages.

1. Treating a problem with your own connection or certificate as a Ministry outage. If the status is Available and only you are affected, Article 106nf does not apply.

2. Confusing scheduled maintenance with an outage. Maintenance is announced in advance and has a different submission deadline: the next business day after it ends under Article 106nh, compared with 7 business days after an outage under Article 106nf.

3. Treating a pending status 100 or 150 as an outage. These are normal transitional processing states. Monitor the same invoice instead of sending it again.

4. Equating a missing UPO with an outage. The invoice may still be processing, may have been rejected, or you may be looking in the wrong session or NIP context.

5. Relying only on social media. An outage in the legal sense is determined by Ministry announcements, not by the number of user posts about problems.

6. Resending the same invoice during an outage. When the system returns, you risk duplicate error 440. Check the original session first.

When KSeF stops responding, follow the same sequence: check the public system status, determine which side the problem is on, choose the correct issue and submission procedure, and then meet the applicable deadline.

These four articles will help with the next diagnostic steps:

How to check an invoice status in KSeF after submission - what statuses 100, 150 and 200 mean and how to interpret session and document status.

Missing UPO in KSeF - a complete diagnosis when the acknowledgement is not visible after submission.

Invoice rejected by KSeF - how to read error codes and what to correct before another submission.

How long do you have to send an invoice to KSeF? - deadlines for online submission, offline24, unavailability and outages in one place.