Intermittent Invalid postback or callback argument?

We're experiencing an intermittent issue with the "Invalid postback or callback argument" exception. In the course of three days we had about 18,000 successful submissions and 7 instances of users being stopped by this exception.

While the submission is successful the vast majority of the time, this is a payment transaction, so the failure rate is unacceptable.

Since the application has passed a rigorous QA process and is functioning as expected in production the vast majority of the time, it would seem like the application code is fairly sound and that there is some other variable that is causing these errors (environment, unexpected user action).

Has anyone else seen this issue presenting intermittently?

Thanks, Ri开发者_Go百科chard

It looks like it was a bandwidth issue!

Using the information in this blogpost, I was able to reproduce the issue and go back to our customer service folks to have them inquire about the user's internet connections. All of the customers that called in to report this issue were on dial-up.

A quote from this blogpost sums the issue up:

"Joe's theory, which I believe to be correct, is that the user might create a postback before their browser even receives the __EVENTVALIDATION form input. This could happen, for example, over a poor connection. The resulting POST won't contain the __EVENTVALIDATION input, and thus ASP.NET cannot validate the postback arguments. The klaxons wail. Glass breaks. The runtime throws an exception."

Thanks all!

I have seen this issue when users re-submitted a form while a previous postback was still being processed. The workaround in this case was to disable the Submit button while a postback was being processed. Would such a scenario be possible in your application?