Same issue here.  Yes I can connect perfectly well to Paypal directly using the same credentials.  I've input them 10 times now so it isn't my typing either.

Thanks for instructions but where exactly do I go for this instruction:

             First, ensure to remove the history of Permissions you've given under Account, then Security on PayPal.

Is this a place in Paypal?  I cannot find it.

I've cleared cache and cookies on my browser (Chrome).  

I've now disconnected the link.

Nothing is working

I can see my Paypal is linked to my Barclays Bank account as normal too.

This is a QuickBooks problem.

Thanks for a speedy resolution.