Quickbooks is not taking this seriously and now I can't connect at all (I've tried reconnecting because of the 90 day rule).  The service team are useless, they offer no refund because of this, despite it being flagged up months and months ago by me, and by so many other people.  If I can't use the app, why should I be paying if you can't sort it out?

And yes, NOTHING you have suggested works.