Microsoft apologises and explains what is causing Outlook, Teams outage

Microsoft says sorry for the Outlook, Teams outageMicrosoft has apologised for the global outage that knocked Outlook, Teams and Copilot offline for millions of users for the better part of a day. It has also finally explained what went wrong. The company says the disruption was caused by "a technical issue not related to cyber or AI / agents." It traces the problem to an earlier network capacity upgrade, where a fault crept in and only showed itself after a more recent network change.The explanation comes nearly 24 hours after users first began reporting trouble on Thursday, around noon US Eastern time. That was close to 10:30 pm in India. Microsoft says it has fixed the underlying issue and is seeing "broad recovery and stability" across its services. Some customers and regions are still waiting for service to return, and the company has promised a full post-incident report once its review is complete.Microsoft's full statement on the Outlook and Teams outageIn a statement shared on social media, Microsoft said:"We are deeply sorry for the disruption this incident has caused our customers and partners. We know the trust they place in our services and take that responsibility extremely seriously. We are seeing broad recovery and stability across our services.This was a technical issue not related to cyber or AI / agents. The incident was introduced by an issue during an earlier network capacity upgrade that surfaced following a recent network change. We have addressed the underlying issue and continue to restore service to remaining customers and regions.Given the scale of demand, we restored services gradually, validating stability at each stage. While this took longer, it helped ensure a stable restoration.We will provide a full post-incident report once our review is complete."Before the formal apology, Microsoft executive Charles Lamanna said the company regretted the impact on customers who "rely on our services to get important work done every day." He added that teams were reviewing what happened and how to stop it from happening again.How the Microsoft 365 outage went from a Teams glitch to a global email failureAccording to Wired, the first signs of trouble showed up around 10:40 am ET on Thursday. At that point Microsoft said it was looking into Teams issues in North America. Just before 1 pm ET, it flagged problems with Exchange Online mailboxes across the Americas. The company first pointed to "elevated load across multiple regions." It later made clear that servers were going offline, and that a surge in traffic was not to blame."We've paused all deployments. We're moving additional traffic off the affected infrastructure, and we're restarting affected servers to return them to service," Microsoft wrote at the time, Wired reported.The fix did not hold. Servers that came back online stopped responding again once traffic reached them. Meanwhile, the servers still running struggled to take on the work of the ones that had dropped out. In one update overnight, Microsoft admitted that its actions so far "have not provided the anticipated relief." Later, it described its progress on patching servers as "marginal success."That explains the slow, stage-by-stage recovery Microsoft mentions in its apology. Along the way, it also extended its email timeout window to 48 hours so that delayed messages would not bounce back. By Friday afternoon, the company said email queues were "significantly reduced and approaching normal levels." North America was recovering faster than Europe and Asia.Outage reports came in from 74 countries and territories within about an hour, according to Downdetector. Reports from India spiked at 11:21 pm local time on Thursday.Airlines, governments and AI tools among those hit by the Microsoft outageIn India, IndiGo said its email support services were impacted and it might not receive customer emails. Akasa Air reported delays. Air India rerouted its emails and said its flight operations were unaffected. A senior executive at a large Indian brokerage said the firm had a backup for Outlook, but client calls on Teams were a struggle. Some businesses running Zoho's workplace tools posted that their day carried on as usual.Elsewhere, Japanese government staff turned to paper copies of documents, and several UK police forces asked people to report crimes by phone. Pharmacies in Britain warned that some patients would have to wait longer for prescriptions because the health service's email system was down. A jail in Colorado could not process online bail payments because it relied on Outlook email notifications. US electric vehicle maker Workhorse Group pushed back its quarterly earnings call.OpenAI and Anthropic also reported trouble with their tools that connect to Microsoft 365.Michigan-based Anderson Economic Group estimates that lost productivity could cost close to $7 billion. It says as many as 51 million users may have had their work disrupted on Friday alone. The think tank also expects that figure to rise. Investors seem less bothered, and Microsoft shares moved only slightly when US markets opened.Security experts are asking users to stay alert as services come back. Scammers often use outages to send fake support messages that try to steal passwords or install malware. Microsoft has also warned that its Safe Links feature may not have been able to check URLs during the disruption, so links in delayed emails deserve a second look before anyone clicks them.While the outage was still going on, Wired noted that cloud failures can come from configuration errors, DNS problems or cyberattacks. Microsoft has now ruled out a cyberattack. Its post-incident report will need to explain how a flaw from an earlier upgrade went unnoticed until a later network change exposed it, and why it took the better part of a day to get millions of inboxes working again.