My point was poorly stated, based on one line of the GP comment: > Azure AD taking down pretty much the entirety of Azure / O365 / Teams is frankly inexcusable

My point was poorly stated, based on one line of the GP comment: > Azure AD taking down pretty much the entirety of Azure / O365 / Teams is frankly inexcusable My objection was that the Microsoft Azure AD service is down, there's nothing that Microsoft can do to protect the services that rely on it. Setting aside your valid x509 counter-argument, the remaining options you listed to increase availability, to me, have to do with resilience of the Azure AD service. They're not alternative services. It depends on where you draw the boundary around the service. Again, clearly Microsoft has failed to provide sufficient resiliency, not arguing against that at all. But once the service is down, practically by definition Teams and Exchange and everything else is doomed.