Technical Questions

I click on the Link of Form action post url and it shows me the error "Invalid merchant id null"

This url is not a visitable url. This is where you need to send the post request message with specific variables and prices to open the bank payment page.

I am trying to make a transaction and I get the error "Invalid orderid (duplicate)".

The orderid must be unique for each request made to the platform.

I am trying to perform a test and it shows me "Security error invalid digest".

This error can be due to many factors. Indicatively:

1) The digest variable has not been calculated according to the documentation

2) Wrong series of variables in the calculation of the Normalized string

3) Wrong name of variables

4) If any of the above does not apply send us an email to with the orderid of the transaction as well as the mid of the business, in order to help you with the resolution of this error.

I am trying to perform a test and I get the error "Merchant not found in system".

It should be checked by you if your request is sent to the correct form action post url (always according to the information we have sent you). You can also check if you have left a space before, after or throughout the field when entering the mid value.

What do I need to send installments in a transaction?

To trade installments, your request to the platform must contain the variables extInstallmentoffset and extInstallmentperiod.

The extInstallmentoffset must always be shipped with a value of 0, while the extInstallmentperiod with a value of 2 to x (maximum number of installments opened in your code) depending on the number of installments you want to send.

For example, for a transaction with 6 installments, the values ​​are sent as follows: extInstallmentoffset = 0, extInstallmentperiod = 6. For a transaction without installments, you must not send any of the above 2 variables.

For the calculation of the digest, all the values ​​of the variables included in the form to be sent are taken into account.

We have changed the hosting server of our website and as a result the IP from which the requests are sent to the payment platform of the bank has also changed.

From our side no action is required as the platform does not perform any control at domain level.

We changed the domain of the company. What do you need from your side?

From the platform side, no change is required as no domain level control is performed. However, the company must inform the competent department of its cooperation bank with a relevant request.

We proceeded to install ssl on our page

No additional action is required on our part, the payments can continue as there is no relevant control at the domain level by the platform.
ConfirmUrl and CancelUrl are defined by you through the request you send to the bank’s payment page. However, the company must inform the competent department of its cooperation bank for the installation of ssl with a relevant request.

Error - Merchant not found in System

Possible Reasons

  • Communicate with the test environment with live codes
  • Communicate with the live environment with test codes
  • They use plugins that do not have to specify whether to hit test or production environment
Background Confirmation

In case he is a merchant in a productive environment he usually notices that he does not receive all the Notification Emails for purchases that have been made in his e-shop. As the response message is sent through the user’s browser, for various reasons the customer may not be redirected to the site so that the response never reaches his Server (such as closing user browser, internet connection).

We inform him about the functionality of the Background confirmation but also that they should handle such messages as they may receive the same response twice. If he answers that he wants this functionality, we activate it first in the test environment

Does not receive Notification Emails

Possible Reasons

  • Unsuccessful transaction
  • Incorrect merchant email entry
  • Incorrect sending of a payer email by the merchant during the transaction


  • Send TXID transactions for which notification emails did not arrive
  • Check merchant or payer email
Error Invalid Digest

Possible Reasons

  • Incorrect calculation of the Digest variable
  • Wrong order of placement of the various parameters in the calculation of the digest
  • Omission of required parameters
  • Incorrect parameter naming
  • Secret Incorrect entry of Secret Key