Hi there,
I know how important it is for you to have access to your QuickBooks Online account either within the desktop app, or in a regular browser. Great job trying the Incognito Mode in Google Chrome! If you're finding that you're able to access your account there, that tells us that this is an issue related to your browser and app's cache and cookies.
To clear the cache and cookies in your browser, follow the steps listed here: How do I clear my browser cache and temporary Internet files?
To reset the app data (thus clearing the cache) in your QuickBooks Online desktop app, click the Help icon on the top menu bar, then select Reset App Data.
The cache and cookies are stored Internet files that cling to the background of your browser or app. It's important to clear them out often in order to allow QBO to run properly.
This should help get things sorted out for you. If you're still noticing issues in the browser or app, please get in touch with our tech support team.
Cheers!