Two weeks after a widespread authentication issue hit Outlook, Skype, OneDrive, Xbox, and other Microsoft services, it's happening again.

On March 21, users across the world began reporting via Twitter that they couldn't sign into Outlook.com, OneDrive, and Skype, (and possibly more). I, myself, am unable to sign into Outlook.com, OneDrive, or Skype at 2:30 pm ET today, but my Office 365 Mail account is working fine. (Knock wood.)

I believe the issue started about an hour ago, or 1:30 pm ET or so.

MSA is Microsoft's single sign-on service which authenticates users so they can log into their various Microsoft services.

As happened two weeks ago, the Skype Heartbeat site posted a message noting that users may be experiencing problems sending messages and signing in:

"We are actively investigating problem, preventing users from signing-in and sending Skype-to-Skype messages! We'll let you know as soon, as issues are resolved."

The Xbox Live status site also notes some users are having issues signing in and managing their contents.

Two weeks ago, Microsoft officials would not comment on the reasons for the authentication issue. I've got a question in again today to see if I can get any information on what's happening or when the problem may be resolved.

As I noted two weeks ago, MSA does not use Azure Active Directory for authentication at present. Microsoft is merging the front ends of the two authentication services, But MSA currently has its own "giant backend data store" of 6.7 billion accounts, according to a tweet from Alex Simons, Microsoft Identity Division Director of PM.

Update No. 1: The Office 365 status page for Outlook.com and OneDrive now has an update which indicates there are problems for those trying to sign into Outlook.com and OneDrive.

Credit: Microsoft

The update says the following:

Title: Can't sign in to Outlook.com User Impact: Users may be intermittently unable to sign in to the service. More info: As the issue is intermittent in nature, users may be able to reload the page or make another attempt successfully. Current status: We're analyzing system logs to determine the next troubleshooting steps. Start time: Tuesday, March 21, 2017, at 5:15 PM UTC Next update by: Tuesday, March 21, 2017, at 7:30 PM UTC

Update No. 2 (3:25 pm ET) : Microsoft is now saying it's "deploying a fix to restore service. Users should begin to experience service restoration as the fix is rolled out."

Update No. 3 (3:30 pm ET). On the positive side, users are starting to report they're able to sign into some Microsoft Services.

On the not-so-positive side, some Azure services also are being impacted by the MSA issue. From the Azure status page:

"Starting at 17:30 UTC on 21 Mar 2017 a subset of customers using Stream Analytics, Azure Log Analytics and other services may experience login failures while authenticating with their Microsoft accounts. Retries may be successful for some customers. Engineers are aware of this issue and are actively investigating. The next update will be provided in 60 minutes, or as events warrant."

Update No. 4 (4:30 pm ET): It seems like most services, including Azure, are no longer experiencing issues with MSA. No word from Microsoft, at least so far, as to what caused this issue for the second time in two weeks.

Update No. 5 (8:30 am ET on March 22): The Office 365 status page indicates that some users may still be having trouble signing into OneDrive. Microsoft officials say the issue is intermittent and may be resolved by repeated login attempts. Microsoft officials said the affected systems are undergoing recovery.

Update No. 6 (4 pm ET on March 22): "Some people may have experienced difficulties logging in to some services. All services have been fully restored," a spokesperson said. I asked again if there would be more coming about the reasons or plans to head off this kind of issue in the future. No word back so far.

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