When Authorize.Net sends a transaction response to your server, the payment gateway waits 10 seconds for a response. If Authorize.Net does not receive a response from your server in 10 seconds, the payment gateway server will time out and display an error page. The first thing you need to check is the order that your script executes. It is very important that something prints to the screen before any other process is started. If your script prints to the screen first, Authorize.Net will recognize that you are receiving the information. The most effective method would be to PRINT the headers, and a line of text such as “Processing, please wait.”
To resolve relay response time outs:
Verify your script permissions and the ability to accept an HTML POST.
Check that the script is not completing other functions before writing to the screen, such as writing to a database or sending e-mails.
See if there are different processes that are used in your script for approvals, declines or errors. Check each process to be sure that they will write to the screen before any other functions.
Check if your script is using redirects immediately upon receipt of the response from our servers. Redirects are discouraged because they can potentially interfere with the process.
Note: On occasion, timeouts will occur that are outside of the control of your script or our servers. Typical reasons for these timeouts are Internet traffic, merchant server overload or malfunctions, or Internet routing issues. Depending upon your server location and what route is used to send data, it is possible that you may occasionally receive a time out message.