Might be a coordinated attack against the network providers that MS uses? MS: Our investigation determined that one of our network connections to a third-party ISP was not taking traffic. We've diverted traffic to alternate channels to expedite recovery. For more information please follow MO273940 in the admin center.

Other source: This is related to a BGP hijack of at least 87.128.0.0/10 belonging to Deutsche Telekom (AS3320) hijacked by AS212416 (Proximity, Bulgaria) passing through AS57344 (Telehouse EAD, Bulgaria) starting at 0633 UTC today.