Our Magento store uses the Website Payments Pro payment gateway through PayPal. For the most part this works pretty well. Occasionally (about once a day), we get failed transaction emails and the errors are very generic (i.e. "Internal Error" or "There was an error processing your order. Please contact us or try again later."). I've been working with our PayPal rep, but he has not yet been able to figure out why. This doesn't happen with every transaction, and typically if the customer re-submits the order it will work the second time. This has been very frustrating for me as the developer, my employers, and the customers who see the same generic error message in a popup dialog box.

My questions are as follows:

1. Is this normal for a site that gets about 300+ orders/day?
2. Are we at the mercy of bugs in the PayPal system?
3. Do any of you have experience with similar problems? Or, on the contrary, do you have experience with a site that gets at least as much traffic and never has any errors with PayPal?

I'm at a loss for what to do. I want to believe that it is not an error in what we are sending to PayPal. But if every client using PP as their gateway experienced this much pain I would think someone with a loud enough voice would be pushing for improvements. I don't have any experience with other payment gateways, so perhaps PP is the lesser of all evils...

• magento
• paypal
• magento-1.5

1. you certainly need to be prepared for issues like this and error messages for clients need to be clear and informative what to do if error happens.
2. yes you are and this can't be only paypal issue this can be n of issues with network latency user interaction etc.
3. there are n amount of sites experiencing this as the system is engineered with lot of break points and you can't assure that issues do not happen on 3rd party system or sites and you can have several precautions to avoid that by doubling the payment methods with several gateways etc.