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

Many users worldwide 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.

A spokeswoman for Microsoft did not immediately have a comment on the outage.