I'm using the Authorize.NET NuGet package, version 1.9.1 (http://www.nuget.org/packages/AuthorizeNet) in a project.  Our call to the library was modeled after the example code in the documentation of the GitHub repository (https://github.com/AuthorizeNet/sdk-dotnet).

On our DEV server, everything works fine [even configured to use live credentials and a live server].  But when we migrate the code over to production [same exact credentials and same live mode], it fails.  From the code perspective, we get a NULL response.  In calling Authorize.NET support, they keep saying "there's no way that we send a NULL response" but I have verified in the code that this is the case.

Doing network traces, we see that the request is being sent, but it looks like our credentials are being rejected from production and the connection is being terminated/dropped.  This is likely why the response is NULL because it's an unexpected termination.

We don't have HTTPS enabled in DEV, but we do in PROD.

Since we're using the NuGet package, there was no option for us to set server/environment other than the boolean flag for RunEnvironment.  We were asked to verify the servers we're using (I assume the NuGet package matches what's in the GitHub respository) and potentitally even change to the non-Akamai servers (not an option that I've seen).  Another option is to potentially turn on any logging within the library, again not an option I've seen.

So, how can we figure out why our connection is being terminated?  Support basically said it was either the credentials (verified to be correct) or the server (no option to change).