That advice is a complete waste of time. I've tried that repeatedly as have our other users. Incognito browsers, set back to defaults, different browsers, flushed dns, disabled firewalls, nothing resolves the spinning green circle. 

But if you have an hour and want to bang your head against a wall, by all means contact their support.

Quickbooks needs to properly addresses this issue, it's too widespread and commonplace. You've discontinued the app for pc and mac, left no options but the browser, so please fix it. I am tired of waiting, reloading pages and losing needless time. Take some ownership of the issue and fix it.