Database Issue gives a no response browser error 1.9.3
Hopefully the detail I can give will help someone to explain to me how to either figure out the problem or to explain to me what the issue is.
On our current site I previously moved all sales & customer details from a previous version on Magento runnning 1.9.1 or 1.9.2 by following this article.
Up until recently we haven't had any configurable products on the site but we do now and when you click add to cart the page hangs and you then get a browser error saying there was nothing given in the response.
I now have a new setup with the same product and everything works as expected, and still works when I move over the customer data. It is only once I move the orders over (all sales tables) that the error is then available on the new setup.
Due to the issue being there for sometime before I discovered it I am going to struggle to look back to figure out how it has been introduced. I don't think it has anything to do with invoice/order references being out of sync because I have made sure these are updated and the issue still persists.
Any suggestions on how I could debug this would be really appreciated as I am currenty struggling to pin point the actual control the add to cart function is located in?