All articles tagged with #exchange online
On August 31, 2026, Microsoft’s Outlook/Exchange Online service experienced a widespread outage, while OpenAI’s ChatGPT Work enterprise agent faced a separate roughly three-hour disruption; both issues were resolved by evening, with no evidence they were linked, underscoring ongoing reliability challenges in enterprise cloud and AI services but not derailing Microsoft’s growth trajectory.
Microsoft is investigating an ongoing Exchange Online outage that is delaying emails to and from external domains and causing intermittent 'Server busy' errors. Anti-spam protections may be contributing to the impact, and a remediation timeline has not been provided. The incident is tracked as EX1467029, with Microsoft continuing telemetry analysis to determine the underlying cause. Previous outages in April and June are noted in context.
Microsoft 365 has suffered a global outage into its second day, preventing access to Teams, Copilot, OneDrive and Exchange Online. Downdetector data showed about a third of users facing problems, with login issues and site access failures. Microsoft confirmed degraded functionality across Exchange Online and other services and said it is applying a targeted authentication component fix while monitoring telemetry for recovery. The issue stems from a core authentication configuration affecting multiple services, with remediation expected to restore authentication, connectivity and search to normal levels as it progresses, though some features such as mail and calendar syncing remain impacted during the outage.
Thousands reported Outlook outages on Aug. 31 as Microsoft noted degraded Exchange Online service; Downdetector tracked peak reports around noon, with recovery actions underway and varying restoration times. Concurrent ChatGPT outages also occurred but were resolved by about 4 p.m., while Microsoft continued remediation with service health updates.
Microsoft acknowledged a widespread outage affecting Exchange Online and several Microsoft 365 services (including Outlook, Teams, and OneDrive) after users reported access issues; the company says the root cause is a core authentication configuration problem and is actively testing a remediation while recovery progresses, with admins advised to monitor updates in the Admin Center as email delivery gradually returns and some features like search may remain affected.
Thousands of Microsoft 365 users reported outages affecting Outlook and other services after a misconfiguration in an authentication component prevented proper deployment. Microsoft is testing a remediation and updating its service health status to reflect broader degradation across Exchange Online, OneDrive for Business, SharePoint Online, Teams and more, with admins directed to incidents EX1464935 and MO1465074 for updates as fixes are validated.
Microsoft is investigating a widespread outage causing authentication failures, connectivity issues, and email delays in Exchange Online, with broader impact on OneDrive for Business, SharePoint Online, Teams, Purview, and Defender XDR. The incident, tracked as MO1465074 (formerly EX1464935), affects tens of thousands of users per Downdetector. Microsoft says a common authentication/protocol failure pattern is under investigation and notes a core authentication configuration issue is being addressed with manual server resets as the scope and remediation continue.
OpenAI’s ChatGPT Work experienced about three hours of elevated errors and latency as the company works on a mitigation, while Microsoft reported degraded Exchange Online functionality; outages affected thousands of users (about 1,100 for OpenAI and around 4,600 for Outlook on Downdetector), and both companies are investigating and addressing the issues.
Thousands of Microsoft Outlook users faced an outage tied to an authentication component issue in Exchange Online. Microsoft says a remediation strategy is being tested on part of the infrastructure before broader deployment, with the incident EX1464935 opened. Down Detector shows thousands of reports, including 37% unable to receive messages, 23% having trouble using the app, and 20% unable to access the website.
Microsoft has patched multiple maximum-severity vulnerabilities in Entra ID, Azure Arc, and Exchange Online that could let attackers with no privileges execute code remotely and escalate privileges. Key flaws include CVE-2026-69836 in Entra ID (deserialization of untrusted data), CVE-2026-65816 and CVE-2026-69555 in Azure Arc, CVE-2026-65801 in Exchange Online, and CVE-2026-65770 affecting an Azure Managed Instance for Apache Cassandra. Patches are in place and no action is required, with exploit code not publicly available. An August update notes CVE-2026-69836 was initially misflagged as exploited in the wild.
Microsoft says it will block legacy TLS 1.0/1.1 for POP and IMAP in Exchange Online starting July 2026, requiring TLS 1.2 or newer. Most users are unaffected since modern clients already use TLS 1.2+, but legacy devices or apps may stop connecting and must be updated. Customers should verify their POP/IMAP clients and embedded devices support TLS 1.2+ and disable legacy endpoints before the July deadline.
A worldwide Outlook.com sign-in outage left some users signed out or seeing 'too many requests' errors; Microsoft says iPhone users must manually re-enter their credentials in the Mail app to regain access. Service health returned to normal by around 7 PM UTC, but the root cause and regional impact were not disclosed. The incident follows other recent Exchange Online/microsoft 365 sign-in outages across Microsoft services.
Microsoft reports an Exchange Online outage blocking mailbox/calendar access across multiple connection methods; by 14:20 EDT the outage was mitigated, but a separate MO1253428 issue affecting Office.com and Copilot sign-in is still under investigation, with post‑incident details forthcoming.
Microsoft says an ongoing Exchange Online incident is caused by a new URL rule that erroneously flags legitimate messages as phishing and quarantines them, disrupting mail flow. The company is reviewing quarantined emails and working to unblock legitimate URLs, with some users potentially seeing previously flagged messages delivered as remediation proceeds; Microsoft has not provided scope or regional impact details yet.
Microsoft says it is investigating a service incident affecting Exchange Online, Teams, and the Microsoft 365 suite (MO1220495) that began on Jan 21, 2026, with users experiencing connectivity and sign-in issues. An Update later pointed to a possible third-party networking issue as the root cause. By the latest statements, access issues were resolved and the service environment remained healthy, but admins should monitor the Microsoft 365 Service Health Dashboard for tenant-specific impact and further updates.