Microsoft is investigating an outage that has left thousands of users around the world, including in Ireland, unable to access Teams and Outlook.
Downdetector.com, which tracks outages, recorded thousands of people reporting problems with Teams, Outlook, Microsoft 365 and XBox Live.
Microsoft tweeted: "We're investigating issues impacting multiple Microsoft 365 services."
Technology Correspondent Jess Kelly says the outage will have a huge impact on businesses.
"A number of Microsoft services have been impacted by the outages this morning including Teams, Outlook, Office 365, and XBox Live.
"Many of these products are used as essential tools by millions around the world, with teams alone having more than 280 million users worldwide.
"The company tweeted this morning to say they've identified a potential networking issue and are working to determine the next steps."
