I am getting a seemingly sporadic error from Authorize.net calls. This is the error that is logged.
[result] => Array ( [response_code] => -1 [response_reason_code] => 0 [response_reason_text] => Unable to read response, or response is empty )
The error started after several months of trouble free operation (~5 orders/day). The customers will get the error and most will just try again. It is usually successful after 2-3 tries. Some customers are successful on their first. This issue has been present for a week now, but it is not consistent. We have had several day long stretches without the error.
I am logging the request and response timestamps and it does not hit the 30 second timeout set in the Magento Authorize.net code. Is there a timeout on the Authorize.net side?
We are on a two server cluster, The error is only happening on one of the servers.
Any clues? I have exhausted my knowledge on this.
Magento Community Edition 1.8.0 Authorize.net (Not Direct Post Method)