You're flowing it wrong: Bad network route between Microsoft, Apple blamed for Azure, O365 MFA outage

Postmortem report emerges for last week's partial downtime

Microsoft says last week's multi-factor authentication (MFA) partial outage, which hit its cloud-based services, was due to a dodgy network route between its servers and Apple's backend.…

via The Register - Data Centre: Networks
http://go.theregister.com/feed/www.theregister.co.uk/2019/10/25/microsoft_outage_explainer/