Just an FYI, Authorize.net is updating some of their requirements for PCI compliance including the use of Akamai SureRoute. There are three new URLs that they would like people to use to interact with Authorize.net. I looked at the extension for v5 and v6 and noticed they are both pointing to secure.authorize.net/gateway/transact.dll. While this URL will remain valid, at least for a while, it is recommended to update this URL to secure2.authorize.net/gateway/transact.dll. I am going to create a GitHub issue for v5, but I noticed that the extensions were removed from the source code in v6. Additional Details can be found here: http://www.authorize.net/support/akamaifaqs/?utm_campaign=February%202016%20Technical%20Updates%20for%20Merchants.html&utm_medium=email&utm_source=Eloqua#newurls Hope you find this useful.