Thank you for the response.

Tried Incognito, other computers, downloaded and tried Mozilla Firefox, all get the same error.  The 'Payment Links' Option is missing from the menu (see attached).

We have other company files we manage with lower QBO license types and it still works.  The two company files we upgraded to QBO ADVANCED immediately broke the Payment Links option.  The Intuit merchant is still connected, we can process 1 invoice payment at a time.  But we lost the ability to generate a custom payment link.  It was working just fine for several months before we upgrade to QBO ADVANCED, and it stopped working.  Called customer service and they said it has been an error since December???