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REDMOND, WASHINGTON (BNO NEWS) — Windows Live Messenger Services and its websites, including Hotmail, are back online after suffering from an hour-long outage on Tuesday afternoon.

Many users, most of them in Europe and Asia, reported receiving a “service unavailable” error when attempting to sign in to Windows Live Messenger, an instant messaging system developed by Microsoft in 1999. The service is best known as MSN, its former official name.

Users were also unable to access the Messenger-related websites, including sites such as Hotmail.com. It was not immediately clear how many users were affected during the outage, which was resolved just after 1 p.m. EST.

“This morning, around 9:30am PST, the Windows Live ID sign-in service experienced a partial outage that caused some customers to not be able to sign into services using Windows Live ID for approximately one hour,” a Microsoft spokesperson said. “The service is now restored to normal. Microsoft apologizes for any inconvenience this has caused customers.”

In an earlier statement, Microsoft said it was aware of the issues and said it was working “aggressively” to resolve the situation.