https://azure.status.microsoft/en-us/status does have an ack
> Impact Statement: Starting at approximately 15:00 UTC Azure customers may experience error notifications when trying to access the Azure Portal. We are aware of this issue and we're currently investigating. Further updates will be provided shortly.
AnonymousSudan is claiming responsibility, which seems pretty likely given their recent success with bringing down other Microsoft services (or really mostly login/landing pages).
Web mirror of their Telegram channel: https://t.me/s/AnonymousSudan
Also, the beta/preview portal works for me still: https://rc.portal.azure.com/