Outlook desktop and Skype for Business users have been having difficulty getting work done today due to the above error message telling them Microsoft is throttling their connection.
The issue was due to a software update for a component that manages authentication requests. The problem lasted about two hours but was resolved when Microsoft reverted the software update.
We identified and reverted an update that was causing multiple services to be throttled. We're conducting tests to ensure that impact has been resolved. Further updates can be found in the admin portal under EX147785 and MO147789.
— Office 365 Status (@Office365Status) September 5, 2018
The issue comes hot on the heels of a problem yesterday which caused outages for Microsoft Azure users in the south of USA, and looks rather bad for a company which based its recent riches on success in the cloud.
Via The Register