This is the first time I meet Microsoft Visual Studio Online Service down, I could not connect to my VS Online Projects, they might call it is User Hub. Some of my source code are on VS Online.
When I tried to login the VS Online account, I could access Visualstudio.com home page without problem, but could not access user hub, got the following error sometimes, or just a timeout message:
VS400664: Sorry, we were unable to retrieve a configured identity provider for you to use when creating an account. If the problem persists, check your web browser security settings. You may need to add https://tfsprodch1acs01.accesscontrol.windows.net to your trusted zones.
And at late of the day, I saw VSO officially posted a message here:
VSO Online - Issues with User Hub - 5/28 - Investigating
Visual Studio Online Team 28 May 2014 3:08 PM 0 Initial Update: Wednesday 28 May 2014 at 10:02 UTC
Description of Issue
Some users may experience issues when clicking on the Users link. In some cases it will show no content or give an error when it is clicked.
If you should experience this behavior, signing out and back in to your account will fix the issue.
Our development team is working on providing a fix. We apologize for any inconvenience this issue may cause.
VS Online Service Delivery Team