Microsoft Office 365 users in the US have suffered two email outages in the past five days.
The cloud-based productivity suite suffered two separate email outages on 8 November and 13 November. Microsoft reported both outages on its Office 365 twitter page. Users have also complained about the recent outages on the company's forums.
"We're investigating mail delivery delays in (North) America," read a tweet from @Office365 last week.
Disruptions in the Office 365 email service started cropping up late last week. Users began writing on Microsoft support forums that they were having issues sending out emails using the cloud-based service.
According to Microsoft's official Office 365 Wiki the 8 November delays were caused by large message queues in the system. After a few hours Microsoft reported that it had fixed the issue and users email service should have gone back to normal.
Services were reported fine throughout the weekend until 13 November when issues began cropping up on Microsoft support forums again.
"On Tuesday, 13 November, some customers served from our North America data centers experienced intermittent access to e-mail services. The issue was resolved and the service is now functioning normally," a Microsoft representative said in a statement.
"During the duration of the issue, customers were updated regularly via our normal communication channels. We sincerely apologise to our customers for any inconvenience this incident may have caused them."
In its statement Microsoft gave no official explanation for its cloud-based email platform experienced issues in the US.
Microsoft unveiled Office 365 last year. The firm heralded the service as a cloud-based productivity suite aimed at businesses. When it was announced some analysts said it would appeal to small to mid-sized business looking for an alternative to on-site hosting services.
The technology giant also recently had a management shake-up. Microsoft parted ways with its head of Windows and Windows Live Steven Sinofsky earlier this week.
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