I am having this same issue for the past few weeks. I can't do my reconciliation that my accountant is asking for. I have tried absolutely everything in the Help pages (clearing cache, clearing Intuit-specific cookies, incognito window, restarting everything. Today I disconnected all the accounts and hit save, but when I tried to reconnect them, I got the same error message. I have spent hours and hours of my time trying to resolve this- it's incredibly frustrating as a small business owner. I am paying for QBO monthly and basically cannot use it. Please resolve this issue ASAP or let us know if there is anything more we can do on our end!