POS Error Codes

POS error codes are response codes that explain why a card payment was not approved or could not be completed. For example, code 51 usually means insufficient funds or insufficient available limit, 54 means the card has expired, and 57 means the card is not enabled for the relevant transaction type.

In this guide you will find the most frequently encountered POS error codes, the likely source of each error, and the steps the cardholder and the merchant should follow.

Important note

The meaning of these codes may vary depending on the card network, the bank, the payment institution and the POS infrastructure being used. For this reason, the description shown on the POS screen, the Paynkolay transaction result and the information provided by the bank always take priority.

What is a POS error code?

A POS error code is a short response given to a transaction by the card issuer or the payment infrastructure during a card payment. This response may indicate that the transaction was approved, declined, requires additional verification, or could not be completed for a technical reason.

For example, code 00 means in most systems that the transaction was successfully approved. Other codes may relate to the status of the card, the balance or limit, transaction permissions, terminal settings, network connectivity or the integration itself.

Not every error code means that the POS device is faulty. Determining whether the problem originates with the cardholder, the merchant, the issuing bank or the payment infrastructure is the first step towards the right solution.

POS error codes — quick reference table

Some codes, such as 93 and 99, may carry provider- or integration-specific meanings. In Türkiye, code 93 may indicate in some systems that the card is not enabled for e-commerce transactions, but this interpretation is not universal. For the exact meaning, the description returned with the transaction should be checked.

What does a leading zero mean?

Some POS screens and reports may display the error code with three digits. In this case the leading zero is usually only for formatting purposes:

1. 051 is usually the same as code 51.
2. 054 is usually the same as code 54.
3. 005 is usually the same as code 05.

Even so, since the same number may be used with different meanings by different providers, no firm conclusion should be drawn from the code number alone.

Most frequently encountered POS error codes

05 — Transaction not approved

05 is one of the general decline codes indicating that the issuing bank did not approve the transaction. Security rules, the card not being suitable for the transaction type, or another decline reason not disclosed by the bank may produce this result.

What should the cardholder do?

1. Check that the card is active and review any usage restrictions.
2. Review notifications in the bank's mobile app.
3. Contact the issuing bank if necessary.
4. Use another card or payment method.

What should the merchant do?

1. Avoid retrying the same transaction repeatedly.
2. Direct the cardholder to their bank.
3. Offer an alternative payment method.
4. Contact Paynkolay support if the error occurs across many different cards.

A short explanation you can give the customer

"Your bank did not approve the transaction. You can check your card settings or your bank's notifications; if you prefer, you can try a different payment method."

51 — Insufficient funds or available limit

Code 51 indicates that there is not enough balance or available limit on the card. For installment transactions, available credit card limit equal to the total purchase amount is usually required as well.

What should the cardholder do?

1. Check the available limit on the debit or credit card.
2. Check whether pending authorisation holds are reducing the available limit.
3. Use a lower amount, a different card, or another payment method.

What should the merchant do?

1. Ask the cardholder to check their balance or available limit.
2. Not split the amount without the cardholder's consent.
3. Offer a different payment option.

54 — Card expired

Code 54 indicates that the card's expiry date has passed. The cardholder should check the date on the physical card and use the renewed card. If payment is being taken with a stored card, the expiry date in the system should be updated.

The merchant may ask the customer to check the date; however, it should not enter card details on the customer's behalf or store them in an insecure environment.

55 — Incorrect PIN

Code 55 indicates that the PIN entered is not correct. The cardholder should re-enter the PIN carefully and should not make many consecutive attempts. Repeated incorrect entries may cause the card or PIN use to be temporarily blocked.

57 — Transaction not permitted for the card

Code 57 indicates that the card does not permit the requested transaction type. The card may not be enabled for online shopping, international use, contactless payment or installment transactions.

What should the cardholder do?

1. Check card usage permissions via mobile or internet banking.
2. Enable the transaction type through their bank if necessary.
3. Use a different card if the permission cannot be enabled.

With the cardholder's explicit consent, the merchant may offer a suitable alternative, such as a single payment instead of installments; however, it cannot change the card's settings.

58 — Transaction not permitted for the terminal or merchant

Code 58 may indicate that the merchant or the terminal is not authorised for the relevant transaction type. Installments, foreign cards, certain card groups or a specific transaction type may not be enabled in the terminal definitions.

1. Terminal and merchant permissions should be checked.
2. It should be verified whether the transaction type is defined on the Paynkolay side.
3. If the problem persists, Paynkolay support should be contacted with the transaction details.

The same card working at another merchant is a clue that the problem may lie with terminal or merchant permissions; however, on its own it is not conclusive proof.

91 — Bank or transaction network unreachable

Code 91 may indicate that the issuing bank or the transaction network is temporarily not responding. Before retrying, it is important to check the transaction status in the Paynkolay panel. If the transaction is clearly seen to have failed, it may be attempted once more a short time later.

92 — Transaction cannot be routed

Code 92 may indicate that the transaction could not be routed correctly to the relevant bank or network. If the same problem occurs with cards from more than one bank, the payment network, the terminal definition or the Paynkolay side should be checked.

94 — Duplicate transaction

Code 94 indicates that the same transaction has already been submitted, or that the system has detected it as a duplicate. Before retrying, the Paynkolay panel, the order status and the authorisation hold on the card should be checked. If necessary, support should be contacted with the order or transaction reference.

96 — System error

Code 96 points to a general system or transaction infrastructure error. First, the outcome of the transaction should be queried; if the problem continues with different cards as well, the integration, terminal connection or payment infrastructure should be checked.

Cards not enabled for online shopping

In Türkiye, cardholders may need to grant permission for their cards to be used for online shopping. If the card is not enabled for online shopping, the transaction may return with different codes such as 05, 57 or 93, depending on the bank and infrastructure used.

For this reason, it is not correct to define code 93 in every system solely as "card not enabled for online shopping". The safest approach is to check the description in the POS or virtual POS response and to direct the cardholder to their bank's card usage settings.

3D Secure verification errors

3D Secure is a security protocol that enables the cardholder to be verified by their bank in e-commerce payments. Verification may be completed via an SMS code, mobile banking approval, a biometric method, or a risk-based frictionless flow.

Some integrations return the 3D Secure result in numeric fields such as mdStatus. Since the meaning of these numbers can vary by provider, a single universal mdStatus table should not be used.

Points to check:

1. Whether the card is enabled for online shopping
2. Whether verification was completed within the allowed time
3. Whether the cardholder rejected the verification
4. Whether 3D Secure authorisation is active for the merchant and terminal
5. Whether the success and failure return URLs are correctly defined
6. Whether the fields are used in the correct order when generating the hash or signature
7. Whether test and live environment credentials have been mixed up

Errors specific to virtual POS

Hash or signature error

A hash or signature error indicates that the payment request failed the integrity check. The following points should be checked in the integration:

1. The fields included in the hash and their order
2. Character encoding and upper/lower case usage
3. Empty or missing parameters
4. Test and live environment keys
5. Amount and currency format

Security keys, card data and signature secrets should never be shared openly in support tickets or emails.

IP restriction

If the IP address of the server sending the request is not registered in the merchant definitions, the transaction may be declined. The server's external IP address, any proxy or firewall egress addresses, and the IP definition on the Paynkolay side should be compared.

Merchant or terminal information error

The merchant number, terminal number or user credentials may be incorrect, inactive, or belong to a different environment. It should be verified that requests are not being sent to the live environment with test credentials, or to the test environment with live credentials.

Currency error

If the requested currency is not enabled in the terminal definitions, or if the currency code is sent incorrectly, the transaction may not complete. The currency, amount format and terminal permissions should be checked together.

Installment permission error

The number of installments may not be compatible with the card, the bank, the sector or the merchant agreement. It should be verified that the relevant installment option is defined on the terminal and complies with legal and operational restrictions.

Timeout and uncertain transaction result

Not receiving a response does not mean the transaction definitively failed. Before resubmitting the same order, the transaction status should be checked in the Paynkolay panel or via the status query service.

Duplicate order number

Reusing an order number that has been used before may cause the new request to be declined or flagged as a duplicate transaction. Order and transaction references must be managed in accordance with the integration rules on every payment attempt.

If the error occurs with only one card, it is likely to originate from the card or the bank. If it occurs simultaneously across many cards from different banks, the merchant account, terminal, integration or payment infrastructure should be checked.

Physical POS and New Generation Cash Register (NGCR) errors

Connection error

A connection error may occur when the device cannot communicate with the bank or the payment infrastructure. The internet, Wi-Fi, mobile data or Ethernet connection should be checked; the device should be restarted safely; and firewall and DNS settings should be reviewed. If the outage continues, support should be requested from the service provider.

Parameter update error

If terminal parameters are missing or out of date, some transactions may not work. The device's parameter loading or update step should be completed; if the error persists, the terminal definitions should be checked with the support team.

Chip read error

The card chip or the card reader may be dirty, damaged or temporarily unreadable. The card should be reinserted; if the rules permit, a contactless transaction can be attempted; if the error also occurs with different cards, technical support should be requested for the device.

End-of-day (batch close) error

The end-of-day process may fail to complete because of connectivity, open transactions, parameters or the bank's response. The description on the device screen should be recorded, the connection checked, and the current end-of-day status verified before retrying.

Fiscal memory full warning

On a New Generation Cash Register, warnings related to fiscal memory may require intervention by an authorised service provider. No unauthorised work should be carried out on the device; the manufacturer's or authorised service provider's guidance should be followed.

TSM or Revenue Administration (GİB) connection error

The device's inability to communicate with the terminal management system or the relevant public infrastructure may indicate a temporary connectivity or service issue. The network connection and the device clock should be checked; if the error persists, the authorised service provider should be contacted.

Fiscal approval or Z report error

Errors and warnings relating to fiscal processes should be handled in accordance with the device manufacturer's procedures. Transaction records should be preserved and authorised service support obtained where necessary.

The correct sequence to follow after a POS error

1. Record the error code and description on the screen exactly as shown.
2. Check the transaction status in the Paynkolay panel.
3. If the outcome of the transaction is uncertain, do not immediately resubmit the same payment.
4. Determine whether the error occurs with a single card or with different cards as well.
5. Note the date and time, amount, order number and transaction reference.
6. Do not record or share the full card number, PIN, CVV or 3D Secure password.
7. In card- or bank-related cases, direct the cardholder to their bank.
8. In terminal-, integration- or infrastructure-related cases, contact Paynkolay support with the transaction details.

Frequently asked questions

What does POS error code 05 mean?

05 is a general decline code indicating that the issuing bank did not approve the transaction. The cardholder should check their bank's notifications, contact the bank if necessary, or use a different payment method.

How is error code 51 resolved?

For code 51, the card's balance or available limit should be checked. Pending authorisation holds can also reduce the available limit. If there is not enough limit, a different card or payment method should be used.

What is the difference between 57 and 58?

57 generally indicates that the card is not enabled for the relevant transaction type, while 58 indicates that the terminal or the merchant is not authorised for that transaction type.

Are 054 and 54 the same code?

In most systems, yes. The leading zero is for formatting purposes, and 054 is used with the same meaning as code 54, which indicates that the card's expiry date has passed. Even so, the transaction description should be checked.

Should a transaction be retried immediately after a POS error?

Not always. Particularly in cases such as timeouts, 91, 94 or 96, the transaction result should first be checked in the Paynkolay panel. Otherwise there is a risk of duplicate charges.

How is a 3D Secure error resolved?

Check that the card is enabled for online shopping, that verification was completed within the allowed time, and that the return URLs and hash settings in the virtual POS integration are correct. Numeric mdStatus values should be interpreted according to the provider's documentation.

In which cases should Paynkolay support be contacted?

Support should be requested, with the transaction details, in the following cases:

1. The same error occurs on more than one card from different banks
2. The transaction result is uncertain, or the panel and the order status do not match
3. There is a problem with the terminal, IP, merchant or installment definitions
4. A hash, 3D Secure response or API integration error persists
5. There is a duplicate transaction or a suspected duplicate charge

Manage your online and in-store payments with Paynkolay

N Kolay Ödeme ve Elektronik Para Kuruluşu A.Ş., operating under the Paynkolay brand, is an electronic money institution authorised by the Central Bank of the Republic of Türkiye (CBRT) under Law No. 6493 and a subsidiary of Aktif Yatırım Bankası.

According to Paynkolay data, the infrastructure serves more than 18,000 merchants and handles a transaction volume of TRY 240 billion. With its PCI DSS Level 1 compliant infrastructure, it offers Virtual POS, Physical POS, Android POS, New Generation Cash Register POS and payment-by-link solutions.

For detailed information about virtual POS and physical POS solutions, you can review Paynkolay products or contact the support team.

Disclaimer

This content is for general information purposes. The meaning of the codes may vary depending on the card network, the issuing bank, the payment institution and the integration used. For a definitive assessment, the description returned with the transaction and the Paynkolay transaction result should be taken as the basis.

Sources

1. Mastercard Transaction Processing Rules
2. EMVCo — EMV 3-D Secure
3. BRSA (BDDK) — Statement on internet use of cards
4. CBRT (TCMB) — Authorised electronic money institutions
5. Paynkolay — Product and corporate information
6. Paynkolay — Frequently asked questions and security information