"iOS users 'must' manually re-enter their credentials to access their accounts via the default Mail app," Microsoft said after a widespread Outlook.com outage that disrupted sign‑ins for users worldwide.
Microsoft confirms global Outlook.com sign‑in interruptions
Microsoft acknowledged the incident on Monday morning, saying customers were experiencing intermittent sign‑in issues that prevented access to mailboxes via Outlook.com. In later updates the company said some affected users were being signed out of their accounts and seeing "too many requests" errors. Roughly 10 hours after the first user reports, Microsoft attributed the disruptions to a "recently introduced change" but did not provide further technical detail.
Service restored but iPhone users must reauthenticate
By Monday evening, around 7:00 PM UTC, Microsoft reported that service health had returned to normal. The company added a mandatory follow‑up for Apple iPhone users: to regain access to Outlook and Hotmail accounts when using the device's built‑in Mail app, users must re‑enter their account credentials. Microsoft published a step‑by‑step procedure that iPhone users should follow:
- Open the Settings app on your iPhone.
- Scroll down and tap on Mail.
- Select Accounts under the Mail settings.
- Tap on the email account for which you need to re‑enter the password.
- Tap Account Settings or the Password field directly (depending on your iOS version).
- Enter the updated or correct password in the Password field.
- Tap Done to save the changes.
- Open the Mail app to confirm that the account is syncing properly and emails are being sent/received.
What Microsoft disclosed — and what it did not
Microsoft declined to share the outage's root cause or to specify which regions or how many users were affected. The company categorized the incident as causing "service degradation" — a label the report notes is typically used for incidents that produce noticeable user impact without taking the service offline for everyone. Beyond the attribution to a "recently introduced change," Microsoft offered no additional technical diagnosis in the public update.
Context: other recent Outlook and Microsoft 365 disruptions
The Outlook.com sign‑in incident followed a string of recent issues Microsoft has addressed. In March the company remedied an Exchange Online outage that blocked customers' access to mailboxes and calendars via Outlook on the web, Outlook desktop, Exchange ActiveSync, and other Exchange Online connection protocols. On the same day Microsoft also resolved a separate problem that caused Microsoft 365 Copilot and Office.com sign‑in problems affecting the Microsoft Copilot desktop app, Copilot in Microsoft Teams, and Copilot in Office apps.
Earlier in April Microsoft resolved a known issue that prevented some Classic Outlook users from sending or replying to emails via Outlook.com; those users had received non‑delivery reports (NDRs) citing error codes 0x80070005‑0x0004dc‑0x000524. Microsoft is also investigating an outstanding problem that triggers "Can't connect to the server" errors when creating groups in Classic Outlook.
What this means for end users, technologists, and enterprises
- End users: iPhone users who rely on the default Mail app must follow Microsoft's reauthentication steps to restore mail syncing and sending/receiving; those signed out may see "too many requests" errors until they do so.
- Technologists and security teams: Microsoft attributed the outage to a "recently introduced change" but has not disclosed root‑cause details; teams monitoring authentication services and Mail app behavior should note the classification as "service degradation" and watch Microsoft service health updates for any follow‑on advisories.
- Affected enterprises and procurement leaders: Organizations using Outlook.com or Classic Outlook should inventory affected user agents (including iOS Mail) and confirm whether internal helpdesk workflows cover the manual credential re-entry step Microsoft specified.
Microsoft has restored service health but has left two practical questions unresolved for customers and administrators: how many users were affected, and what precisely in the "recently introduced change" triggered the sign‑in failures. Until Microsoft provides further detail, users must follow the published reauthentication steps and IT teams should monitor the company's service health messaging for any additional guidance.
