My ISP (Telefonica) currently doesn't return addresses for login.microsoftonline.de (cloud Germany) while Google's DNS servers do. I wonder if that's related.
Interesting, I suspecting their 'restart' of 'authentication infrastructure' may be a rolling restart and perhaps they have not got to Germany yet, perhaps by using Google's DNS different 'authentication infrastructure' is being provided?
Moving to another Provider might involve shifting to other ips. Probably sucks to be working there right now.