I am having an issue with Authorize.net SIM checkout via Zen Cart 1.3.8a. We would use the AIM version but we are a very small nonprofit company, SSLs aren't cheap, and we aren't experienced at installing one. Our server is a Windows XP machine currently being tested from behind a campus network (we all share one outside IP address). I have plenty of memory and harddrive space. The internet connection is pretty speedy. We are using WAMP server to manage our hosting.

I am having an error wherein when someone clicks the final "submit" button on the Authorize.net page, it tells them:

"An error occurred while trying to report this transaction to the merchant. An e-mail has been sent to the merchant informing them of the error. The following is the result of the attempt to charge your credit card."

Shortly after, I get an email saying (amongst other things):

"Your script timed out while we were trying to post transaction results to
it. Transaction ID: 0
Transaction Result: This transaction has been approved."

I have read some of the other threads similar to mine, but none of them offer workable solutions.

I am wondering if y'all think this might be due to our server currently being behind a campus router. It isn't a live website yet.

Thanks for your help!