Hi,
HikaShop payment log file will contain debug information if you try with the "debug" setting activated in the settings of the payment method.
However, checking the code of the plugin, I can see that the AIM mode is missing debug logging.
We'll add that. You can add it too by adding the code
if($this->payment_params->debug){
hikashop_writeToLog($vars);
hikashop_writeToLog($post_response);
}
in the onBeforeOrderCreate function just before the line:
Otherwise, you can switch temporarily to SIM mode so that you can get the debug since it should normally produce the same error as the AIM mode.