Invalid State Error: What’s a Poor Person to Do?

So, the user had just booked their ticket and was choosing their seat assignments when, out of no where, comes this error message:

What should the user do with this little tidbit of information?

An “Invalid State Error” sounds like someone entered the wrong US state abbreviation, but the system a minute ago confirmed the reservation. Someone who doesn’t understand how a digital state machine (like a web server) works probably won’t recognize that error message.

The conditions for the problem are also not very informative, since they are all wrong. In this instance, the user had been interacting with the system without any breaks that took more than a minute, there were no multiple browser windows open, the back button hadn’t been used, and there was no use of bookmarked pages. Not one of these conditions is actually true.

And what does “Please start over.” mean? Is the reservation lost? (Turns out: no.) Were the seat assignment changes lost? (Turns out: no.)

There is no button to start over. Our user wondered if they needed to make a second reservation (that would’ve been a disaster). Fortunately, they were a savvy enough traveler to check out the “Existing Reservations” link hidden deep in AA.com’s menus and found the reservation was there, intact, and all set.

This user didn’t leave the site with a lot of confidence in American Airlines or the site.

How many messages like this does your site have embedded deep in their code? What happens when a user hits one? What kind of experience do they have?