The problem apparently lasted for more than three hours and involved a networking hardware problem that affected customers in North America, according to updates posted by Microsoft on the and by administrators in .

BPOS (Business Productivity Online Suite), which includes Exchange Online and SharePoint Online, has been hit by various outages dating back to August of last year.

Microsoft has at different times acknowledged the problems and apologized for them, pledging to do better.

In a statement on Wednesday, the company said the problem started at 11 a.m. U.S. Eastern Time, and confirmed that "network equipment issues" in the data center were to blame.

"All services have been restored. During this incident, customers were updated via social media channels, as access to the Service Health Dashboard was impacted by this incident. We apologize for any inconvenience this has caused our customers," the statement reads.