Microsoft Outlook users reported sign‑in problems starting just before 5 a.m. ET on Monday, with outage reports peaking early in the day as some people found themselves unexpectedly signed out of their accounts.
Downdetector tracked the spike, reporting about 1,500 problem reports at the height of the disruption. In a message to users at 3:36 p.m. ET, Microsoft said internal logs tied the issue to a recent configuration change and that it had rolled back the update. "After reviewing the logs collected from internal reproductions we've found a pattern of errors that point to a recent backend configuration change that may be causing impact," Microsoft said, and added that it had already reversed the change.
Microsoft followed up at 4:01 p.m. ET with another status update saying the rollback was complete and that monitoring showed recovery. "The roll back of the previously mentioned configuration change is complete and our telemetry indicates service health is recovering," the company said. Microsoft also noted in a recent status report that the service appeared to be recovering.
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The company acknowledged the problem primarily affected Outlook.com sign‑ins on mobile apps. "We're working to mitigate an issue that may cause some users to experience intermittent Outlook.com sign‑in failures on mobile apps," a Microsoft spokesperson said, and Microsoft warned that some people logging into Outlook.com might experience intermittent failures, including too many requests errors.
Apple iPhone users were singled out in the status updates: Microsoft said people using iPhones might have to reenter their passwords in Settings to access Outlook accounts again after the disruption. Downdetector also reported iOS app problems and tracked outage reports throughout the day, underscoring the trouble for mobile customers.
There is a small gap between Microsoft's recovery signals and the experience of affected users. Some people reported being signed out unexpectedly, and while Downdetector later showed fewer than 1,000 concurrent errors for the first time since the outage began, the platform's earlier peak shows the incident briefly touched a large number of accounts. Microsoft said it was still working to mitigate intermittent sign‑in failures on mobile apps even as telemetry improved.
The facts on Monday point to a single operational fix as the turning point: a backend configuration change that Microsoft identified, then reversed, after which its monitoring suggested service health was returning. For users, the practical next step is clear—check device settings and, if necessary, reenter passwords on iPhones to restore access. For the service, the rollback appears to have stabilized sign‑in behavior, but Microsoft will need to confirm over the coming hours that intermittent failures do not reappear.
