I’ve already submitted an appeal and also spoke with the App Review team over the phone. Unfortunately, both the appeal and the call ended with the exact same response, without a proper review of the actual app.

Same here. My app approved and listing in market but my in app purchases not working. This is so bad.

I have same issue. There is no problem on my device and simulator. But Apple Tester takes this error on review. So my app rejected. "Error 23: There is an issue with your configuration. Check the underlying error for more details."