thanks for the additional information.  I have used multiple browsers on Mac, basically Chrome and Safari.  I have tried private / incognito mode on both, mobile and desktop.   I do not have popups blocked.  I also tried different network connections and disabled iCloud private relay service as well.  

NONE of the actions above changed the behavior of the connector.    This appears to be a cloud to cloud issue between QB and shopify, not a client side problem.

I am clearly not an exception here.  the thread certainly shows that