I am have the same exact issue as the original poster. I have checked EVERYTHING you mentioned, none of it fixes the problem. None of the customers/items/accounts that are inactive have been changed within the past several months. This problem just started late last week. I think it's related to the awful update that Quickbooks did to their online invoices, but I don't know how to fix it. I cannot even create an invoice. This is a huge problem that needs to be fixed immediately.
Since I've checked everything on my end that you mentioned, and none of that was the problem, what can I do?
