Setting up a log file
During the implementation phase, it is important to have logs especially in case of difficulties with signature computation.
It is recommended to set up a daily log file even after shifting the merchant website to live mode.
It will allow you to analyze data in case any problem occurs.
Ideally, a log file should contain the sent or received data, the chain obtained during signature computation before applying the hash function.
HTTP error code
In case an error occurs during notifications, the sent warning e-mail will specify the return code of the HTTP protocol.
There are 5 categories of return codes:
A description of the error codes with their possible causes is available on our website
An .htaccess file might block the call to the IPN.
.htaccess files are Apache web server configuration files. They can be stored in any folder of the merchant website (the configuration applies to the folder and all the contained folders with no .htaccess files).