POST /Templates/{templateId}/Order/{orderId}/Confirmation (problem with 15.1)

Here is a problem we are seeing since our recent upgrade from 14 to 15.1.

This is a custom web site, and we send order confirmations from here. The rendering of the confirmation email is done on the Tessitura side.

We are now sporadically getting a 400 response code on the /Templates/{templateId}/Order/{orderId}/Confirmation call. The error message is "Specified LoginName already exists for this WebLogin."

Without going too deep into the web code, I can confirm that:

1. The constituent doing the checkout (POST Web/Cart/Checkout thinly wrapped) is the same as the one making the render call. They happen in succession.
2. The constituent is "special" (named anonymous) and handles more orders than typical.
3. Not all render calls in this situation fail. 80% to 90% succeed. It's not clear how to replicate this.

More mysterious behavior:

1. The response body has always been correct so far. Only the response code is 400. (Ignoring it will likely be our workaround for now.)
2. When testing, the same call failed, occasionally. But the error message was about seat locking! Again, it was random, we couldn't replicate it.

BTW the template has no strange code. It's essentially the example template that ships with Tessitura, with extra markup.

Maybe a minor bug in the rendering call?

Tushar Samant

Chicago Architecture Center