When integrating towards DIBS Flexwin or DIBS Payment Window you can specify a "callbackurl" parameter. A server to server call is made, to the url specified in the parameter, when the transaction is processed.
The conditions for this function to work are that the shop's servers are online, and that the callbackurl is correct. By default the call is only made once by the DIBS servers.
However, you can select to activate "repeated callback" (up to 5 times with appropriate time intervals), if the first callback fails. If there are still issues hereafter, the callback is dropped, and an e-mail is sent to the given e-mail address, and the transaction is marked with a red star "*" in the transaction list.
The email contains the transaction number of the failed callback, date and time for the first and last attempt, as well as a description of the error.
The error may be a failure to establish a connection to the shop's system, or an http error. In case of the latter, the http error will be added in the error description (see Status Code Definitions). If the original content of the authorisation request is missing, the following error message is sent: "Illegal request: it is empty".
The the port number of the original authorisation request is outside interval, the following error message is sent: "Illegal portnumber".