A global Microsoft 365 outage affected governments and businesses in the United States: which services stopped working

The global Microsoft 365 outage affected communications and administrative operations of local governments and businesses in the United States. (Europa Press) The global Microsoft 365 outage caused communication problems and disruptions to administrative activities of local governments and businesses in the United States. The effects were recorded in North Carolina, California, Oregon, Texas, and New Mexico, while a company in the Detroit area had to modify its corporate schedule. The incident began on November 12 and was still under investigation the following day. The problem mainly affected Exchange Online, the cloud service used to manage Outlook mailboxes, although it also reached functions of other Microsoft applications. The failure made it difficult to access messages, calendars, and work tools that public and private organizations use to maintain their operations. Notices issued by local authorities and businesses showed various consequences: from delays in serving residents and difficulties receiving communications to the suspension of virtual appointments and the postponement of a financial conference. Meanwhile, Microsoft reported progress in its work to restore infrastructure stability, but had not yet confirmed the full resolution of the incident. The official Microsoft 365 Status account reported on November 12 that it was investigating reports from users in the Americas who could not access their Exchange Online mailboxes through various connection methods. This service is used to manage business email and constitutes one of Outlook's core tools. As the investigation progressed, the company warned that the problem could extend to customers in any region. It also identified an overload in part of its infrastructure after several servers unexpectedly went out of service. According to Microsoft's explanation, the increased load was not due to a general increase in traffic. The servers that remained operational had to also process the requests that corresponded to the affected machines, which reduced available capacity and generated connection errors. The company identified problems in a process related to server health checks and secure connections. When that mechanism failed, some machines stopped responding and lost the capacity to handle user requests. The outage also reached functions of other tools. Among the services that could experience difficulties were Microsoft Teams, SharePoint, Copilot, Planner, Intune, and Microsoft Defender, in addition to certain functions of the Microsoft 365 admin center. However, the company clarified that not all features of those applications were necessarily out of service. Functions that depended on the connection to Exchange Online could be affected, while those that did not need to interact with email could remain operational. To recover the infrastructure, Microsoft applied various measures: it restarted affected servers, rerouted traffic along other paths, temporarily halted some deployments, and modified monitoring mechanisms to facilitate the recovery of the machines. It also worked on configuration adjustments related to authentication and connection routing. Microsoft ruled out malicious activity on the servers while it worked to stabilize its infrastructure. (Europa Press) In Cumberland County, North Carolina, authorities reported on November 12 that the outage was affecting Outlook and other Microsoft 365 products used by the local administration. As a result, county departments and employees could not temporarily send or receive internal or external emails. The notice also warned of possible difficulties in offices that receive or manage calls and voice messages via email. Given that situation, authorities recommended that residents and community organizations communicate by phone or visit the relevant offices in person. In Burbank, California, the municipal government announced that the city's email service was affected. The administration warned that its employees might have difficulty sending and receiving messages, so responses to residents' inquiries could be delayed. The municipality asked those who needed assistance to call the relevant departments directly, rather than relying on email communications. For its part, Portland, Oregon, reported that numerous municipal employees had lost access to email. The outage had concrete consequences in the Permits and Development area, which suspended the 15-minute virtual appointments scheduled for November 12. The city announced that it would contact affected users to reschedule the meetings once service returned to normal. In this way, the incident also disrupted activities related to administrative services and the processing of procedures. In Lago Vista, Texas, municipal authorities reported that the outage was affecting the email and calendar services used by their employees. The problem made it impossible to reliably send and receive messages and hindered access to Outlook calendars. The administration noted that Microsoft had acknowledged the incident and was working to restore the affected functions. However, at the time of issuing its warning, it did not have an estimated timeframe for recovery. The outage of the calendars represented an additional difficulty for organizing municipal activities, since these tools allow meetings, commitments, and tasks to be coordinated among different departments. In Los Alamos County, New Mexico, authorities also confirmed that the county's email system had been affected by the global Microsoft problem. The notice included other Microsoft 365 tools, although it did not detail which departments had suffered the greatest difficulties or the extent of the outages in each service. The notices from Texas and New Mexico expanded the list of public administrations that acknowledged problems in their institutional systems. Nevertheless, the documented consequences were different in each jurisdiction, and not all reported the suspension of in-person procedures or services. Corporate tools such as Microsoft Teams, Copilot, and SharePoint experienced problems in email-related functions. (Ed Hardie/Microsoft) The outage also had consequences in the US private sector. Workhorse Group, an industrial technology company based in the Detroit area, announced on November 12 that it was postponing the conference call scheduled to present its third-quarter financial results and business outlook. The meeting was scheduled for that Thursday at 4:30 p.m. Eastern Time. However, the company announced that the disruptions caused by the global Microsoft outages forced a change in the schedule. The company rescheduled the conference for Monday, November 16, at the same time. The decision was directly linked to the operational problems recorded that day and constituted one of the documented cases of business impact in the United States. The postponement altered Workhorse's financial communication calendar, as the company was to present information on its performance and expectations to investors and other market participants. In its updates on November 13, Microsoft announced that it was beginning to observe greater stability in the affected servers after applying changes to a component related to authentication and connection routing. The company noted that it was progressively expanding recovery measures to other parts of its infrastructure, prioritizing the regions that were within their peak activity hours. It also continued monitoring server behavior to prevent them from failing again when receiving traffic. Another problem the company sought to address was the accumulation of messages that could not be delivered during the outage. To reduce the risk of those emails expiring before reaching their recipients, Microsoft extended the wait time for delayed messages to 48 hours. Despite the progress, the company warned that some users could still experience intermittent difficulties connecting to their mailboxes. In its most recent update, it had not yet declared the Exchange Online incident fully resolved. Microsoft indicated that it had no knowledge of malicious activity causing the problem. In addition, it noted that once the situation was mitigated, it would publish a follow-up report with more detailed information on the causes and corrective measures.