How to fix gateway timeout error?

Session timeout issues with Zencart

• Random session timeout errors occurring on Zencart 1.5.1 & 1.5.3 installations. Host is Dreamhost - PHP 5.4.11. Version 1.5.1 site was working fine before upgrade from PHP 5.2 to 5.4. I need advise on getting the error fixed. I have an existing installation of Zencart 1.5.1 that was working fine until Dreamhost upgraded the domain to PHP 5.4.11. Now, randomly, the site throws a session timeout error when a customer hits the final submit button to complete an order or hits the submit button to create an account. It's not every single time, maybe every 10 times at most. After the error during an order, it takes two or three tries to log back in to the account, but then the order generally goes through with no problem. I posted about this on the Zencart message boards and received very few suggestions. I tried them all and it made no difference. I can provide a link to that if needed. Version 1.5.3 was released last week, so I decided if I could get it installed and working, I would just cut my losses on the old installation, but I'm getting the same error again. Fresh database & installation, different domain, same host. Posted again to the ZC message board and the response was "have you considered a new host?" Yes, I have, but this is a huge site and I don't want to move when it's probably something with a PHP setting that could be fixed pretty easily. The ZC compatible hosts listed on their site are no better than Dreamhost - bluehost, host monster - no thanks. I installed 1.5.3 with no issues and then did the following: 1. Changed flat rate shipping from $5 to $4 2. Set up my one tax zone/rate 3. Set up Authorize.net AIM module 4. Set up one test product I then did the following: 1. Set up test customer #1 and placed a test order using Authorize.net as payment method - all was well 2. Set up test customer #2 and placed a test order using Authorize.net as payment method - all was well 3. Set up test customer #3 and placed a test order using Authorize.net as payment method - all was well As I clicked the submit button to set up test customer #4, I got the same session timeout error as detailed in the thread above - "Whoops! Your session has expired. If you were placing an order, please login and your shopping cart will be restored. You may then go back to the checkout and complete your final purchases. If you had completed an order and wish to review it." I'm on a Mac (using Chrome, Safari & Firefox browsers) and I have customers with practically every other variation of operating system and browser that get the same error randomly as well. The error has come up randomly for the last few months, since Dreamhost upgraded me to PHP 5.4 from 5.2. I've compared PHP session settings with another user and the only difference was in session.hash_bits_per_character - she had 5 and I had 6 for that setting. I couldn't find any other FAQ pages that listed a fix for this problem, so if anyone has any suggestions, I would love to hear them! :)

• Answer:

  Do you use a single server or multiple? Multiple might make for a need for sticky sessions.