"Diia.Sign" has become one of the main tools for Ukrainians' electronic interaction with the state and businesses. It can be used to sign electronic documents, verify one's identity, and authorize oneself in information systems that support the relevant integration.
However, anyone may encounter a situation in which "Diia.Sign" does not activate, the photo verification fails, signing cannot be completed, or the required service does not respond to the request at all. The reason does not necessarily lie within "Diia" itself. The problem may arise on the smartphone, during identity verification, or in the information system where the user is trying to obtain a service.
How to resolve such a situation and use the service is explained by UNN.
What is "Diia.Sign" and how does it actually work
"Diia.Sign" is a remote qualified electronic signature. It is an electronic equivalent of a handwritten signature and makes it possible to identify the signatory and confirm the authenticity and validity of an electronic document.
To create such a signature, a person needs to log in to the "Diia" app, go to the relevant section in the menu, create a signature, pass photo verification, and set a five-digit code. This can be done free of charge. "Diia.Sign" remains valid for one year, or until the person deactivates it.
Individuals who want to obtain such a signature must have an ID card (which replaces the Ukrainian citizen's passport booklet) or a biometric international passport in the mobile administrative services app "Diia". During verification, the system compares the image taken by the user with the photograph in the document. The resulting facial image is needed directly for verification. After verification, the system deletes the photo .
The personal key of "Diia.Sign" has a special architecture. One part of it is stored on the user's smartphone, while the other is held in a special secure device of the qualified electronic trust service provider "Diia." Therefore, merely knowing the PIN code is not enough if an intruder decides to use the signature. Before signing, the user must pass photo verification and enter their code.
This feature also explains why "Diia.Sign" is linked to a specific device. If a user switches to another smartphone, they need to log in to "Diia" on the new device and create a new "Diia.Sign." The system deletes the previous one. Likewise, the signature is not retained after logging out of the account or deleting the app.
Why "Diia.Sign" may not work
There may be several reasons, and not every error means a large-scale failure of "Diia."
The most common problem point is photo identity verification. It is mandatory both when creating the signature and when using it. The system compares the user's face with the photograph in their electronic document. If the verification is not completed successfully, it will not be possible to sign the document.
The problem may also arise after changing smartphones. Since part of the key is stored directly on the device, an already created "Diia.Sign" cannot be transferred to a new phone. It will have to be created again. We should separately emphasize that after February 2026, in order to create an e-signature in the mobile administrative services app, one should purchase a smartphone with NFC scanner technology. It is needed to read biometric documents.
It is also worth checking whether the user has logged out of their account or reinstalled "Diia." In both cases, the previous "Diia.Sign" is deleted, so it must be created again after logging in once more.
Another group of reasons is related not to the signature itself but to a specific electronic service. "Diia.Sign" is integrated into the information systems of government bodies, enterprises, and other organizations. Therefore, a situation in which it is impossible to log in or sign a document on a specific portal does not in itself prove that the e-signature has stopped working. The failure may also occur in the service that receives it.
Finally, temporary technical problems with the "Diia" app itself or government information resources may occur. In such a situation, the user cannot always resolve the problem independently, and repeatedly reinstalling the app is unlikely to make the government server care about their deadline.
What to do if photo verification fails
First of all, make sure that your smartphone camera is working properly and has access to the app. During face verification, follow the instructions that appear directly on the "Diia" screen.
It is important to distinguish between the service's official requirements and general technical recommendations. For example, online sources often advise users to обязательно remove their glasses, hold the smartphone strictly at eye level, or perform a specific sequence of head movements. The official instruction of the "Diia" Qualified Electronic Trust Service Provider does not contain a universal set of such requirements. Therefore, you should primarily follow the prompts displayed by the app during the specific verification. At the same time, in practice, you should ensure that your face is well lit, make sure the front camera lens is clean, and ensure that your face is clearly visible.
If verification repeatedly ends in an error, it is advisable to close and restart the app and check your internet connection. It would also be worth updating the app itself in the official Play Market store. Restarting the smartphone may also help resolve a local software malfunction.
However, the widespread information online that "Diia.Signature" usually stops working because of a VPN should be treated with caution. The official instructions on the administrative services portal describing the creation and use of the signature do not establish a general ban on using a VPN. Therefore, disabling the VPN may be a way to test the network connection, but it would be incorrect to call it a confirmed typical cause of the malfunction.
How to create a Diia.Signature again
If the problem is specifically related to a previously created signature, the user can deactivate it. This can be done directly through the app on their smartphone. To do so, open the "Diia" menu, go to the "Diia.Signature" section, and select deactivation. After that, the signature can be created again by repeating photo verification and setting a new five-digit code.
How to determine exactly where the failure occurred if "Diia.Signature" does not work
If "Diia.Signature" does not work when using a particular government or commercial portal, it is useful to check whether other app functions work and whether the same problem occurs in another service that supports an e-signature.
At the same time, checking ordinary authorization on the "Diia" portal is not an accurate test of whether the service is functioning properly. Authorization, receiving an electronic service, interaction with a government register, and applying a qualified electronic signature may use different components of the digital infrastructure. Therefore, it is entirely possible for one function to work while another does not.
If the problem is widespread, information about technical maintenance or malfunctions may appear on the official resources of "Diia" and the Ministry of Digital Transformation. In the event of a failure involving a specific register, it is also worth checking announcements from the body that administers it.
What can replace "Diia.Signature"
If a document needs to be signed urgently, it is not necessary to wait for "Diia.Signature" to be restored. Other qualified providers of electronic trust services operate in Ukraine and can issue a qualified electronic signature. The list can be found on the website of the Central Certification Authority.
You can also use a qualified electronic signature issued by the Qualified Electronic Trust Service Provider of the State Tax Service. To obtain electronic trust services for the first time or after the certificates expire, a person must prepare the necessary documents and contact the relevant registration point. For holders of valid State Tax Service certificates, the service provides a number of remote operations, including the reissuance of certificates.
Qualified electronic signatures are also provided by banks and private qualified providers. However, it is worth bearing in mind that in this case, the terms, key format, method of obtaining it, and supported services depend on the specific financial institution.
A document can also be signed using a valid key, in particular via the Diia QES web service. It supports personal keys and certificates from all qualified providers of electronic trust services. According to the service, the user's file is processed directly in the browser during signing and is not transmitted to the provider's side.
Can BankID replace Diia.Signature?
The NBU's BankID is often mistakenly included among the alternatives to a QES. In fact, these technologies perform different functions.
The NBU's BankID is an electronic remote identification system. It allows the bank where the user has already completed identification to transmit the necessary personal data to the institution where the person is receiving an online service. That is why BankID can be used to log in to many government, financial, and commercial services.
However, a user's BankID is not the person's QES and therefore cannot automatically replace "Diia.Signature" where legislation or a specific electronic service requires the application of a qualified electronic signature. The confusion usually arises because, when information is transferred via BankID, the bank itself applies its QES or qualified electronic seal to the data. However, this protects and verifies the data transmitted by the bank; it does not create the client's personal QES.
Where to turn if Diia.Signature still does not work
If the standard steps have not helped, the problem keeps recurring, or the app constantly displays the same error, it is worth contacting the official Diia support service. This can be done via the official support Telegram channel. The request should include the smartphone model, the operating system and app versions, a description of the exact stage at which the problem occurs, and the precise text of the error message. If technically possible, a screenshot should also be attached.
At the same time, do not provide third parties with the PIN code for "Diia.Signature," passwords, bank card details, or any other information that is not required to diagnose the technical problem.
What users of the service should remember
If "Diia.Signature" suddenly stops working, this does not mean that the user has lost the ability to sign electronic documents. First, it is worth determining exactly where the problem occurs: during photo verification, in the app itself, when interacting with a specific website, or when applying the signature.
If the problem is local, restarting the app, checking the internet connection, updating Diia, or creating the signature again may help. If the failure occurred on the side of an external system or state registry, reinstalling the app will not fix the situation.
For urgent documents, it remains possible to use another valid QES from a qualified provider, if the specific service supports it. BankID should be regarded specifically as a means of remote identification, rather than a universal replacement for an electronic signature.
The main rule in the event of a technical problem is not to deactivate the signature or reinstall the app unnecessarily. It is better to first check whether "Diia.Signature" is actually malfunctioning, rather than the website or electronic service in which the user is trying to use it.
Let us remind you
Earlier, we wrote that the "Army+" app launched multiple-signature support for reports. This innovation significantly speeds up the document approval process, reducing the administrative burden on military personnel.