Office 365 comes in a variety of editions that vary in price and in the applications and tools they include. Most Office 365 editions come with Exchange Online, SharePoint Online, Lync Online and OneDrive for Business, and some also include the full-featured Office productivity app suite.
The basic version of Office 365 for Education, called A2, is free, while the most sophisticated version for businesses, Office 365 Enterprise E4, costs US$22 per user, per month and includes a 99.9 percent uptime guarantee.
A Microsoft spokeswoman contacted via email acknowledged the problem, but didn't provide details about the number of customers affected.
Juan Carlos Perez covers enterprise communication/collaboration suites, operating systems, browsers and general technology breaking news for The IDG News Service. Follow Juan on Twitter at @JuanCPerezIDG.