Microsoft's Outlook and Hotmail services are currently offline for unspecified reasons, leaving millions of customers without access to their emails.
On a status page the firm has confirmed both services are unavailable, and no detailed information has been provided on the cause of the problem. The incident first surfaced late last night.
"We're having a problem accessing email. You might not be able to see all your email messages. We're working to restore service right now," it said in an update at around 10pm - although the US time zone wasn't specified.
This morning is said the problem was still not fixed and would provide more information later this afternoon.
"Fixing the problem is taking longer than we hoped. We'll provide an update by 13:12. We apologise for the lengthy interruption in service."
V3 contacted Microsoft for further insight into the outage but the firm merely issued a stock response.
"Microsoft is investigating an issue affecting customers' access to Hotmail and Outlook.com, and we are working to restore full access to the service as quickly as possible."
V3 was able to access an Outlook email account, suggesting the problem could only be affected certain users.
We'll update the story as more information becomes available.
The incident is no doubt likely to embarrass Microsoft as it fights to compete with Google in the email market, having seen its lead at the top of the market disappear due to the popularity of Gmail, which now boasts some 425 million users.
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