Microsoft's cloud email services including Exchange Online have been disrupted by problems coming from a US-based datacentre.
The issues, which led to some customers seeing their e-mails delayed by up to two hours, according to posts on an official Microsoft support forum, occurred on Thursday.
"We are investigating reports of intermittent mail flow issues affecting Exchange Online users served from the Americas datacentre," a Microsoft representative wrote on the forum at the time of the problems.
The delays were dealt with later in the day, Microsoft told ZDNet UK's sister site ZDNet.com. One percent of the Business Productivity Online Services (BPOS) users were affected by the sluggish emails.