Update - Wed, Mar 19 2014 1:00 AM
We applied the fix and all the impacted users (350 accounts) should be able to access their accounts now.
Thanks for your patience, we apologize for any inconvenience.
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Initial - Tue, Mar 18 2014 11:45 PM
We are currently experiencing login issues on VSO Services that impacts subset of users (< 350 users). This issue was introduced with our recent Service maintenance, where we are now throwing errors for users who have had their PUID changed by LiveID in the past, We store the PUID in our Identity system and VSO service relies on it as unique identifier for a user. DevOps engaged and working on the fix, We apologize for the inconvenience.
Thank You