Cannot Access Email Account on Browser, Outlook App, Desktop or iOS HELP

Question

The following error is appearing accross all my platforms when I try to access this email account I use for both personal and business:

UTC Date: 2025-09-11T21:48:08.480Z
Client Id: REMOVE PII
Session Id: b52c9061-a570-4124-8a42-0049ad186f63
Client Version: 20250905004.03
BootResult: transient
Back Filled Errors: Unhandled Rejection: SyntaxError: Failed to execute 'json' on 'Response': Unexpected end of JSON input:undefined|undefined:undefined|undefined:undefined|undefined:undefined|Unhandled Rejection: SyntaxError: Failed to execute 'json' on 'Response': Unexpected end of JSON input:undefined|undefined:undefined|undefined:undefined|undefined:undefined|undefined:undefined|undefined:undefined
err: Error: 503|X-FEServer
esrc: StartupData
et: ServerError
estack: Error: 503|X-FEServer
    at Object.w [as createStatusErrorMessage] (https://res.public.onecdn.static.microsoft/owamail/hashed-v1/scripts/owa.mailindex.64256ed1.js:1:1041)
    at https://res.public.onecdn.static.microsoft/owamail/hashed-v1/scripts/owa.mailindex.64256ed1.js:1:164464
st: 503
efe: YT3PR01CA0106

Answer 1

Dear Caitlyn LeBlanc
Thank you for reaching out through the Microsoft Q&A forum.

We sincerely regret the inconvenience you're experiencing. We understand how essential uninterrupted access to your mailbox is, and we recognize the disruption this issue may be causing to your daily operations.

Microsoft has officially acknowledged the problem, which is currently affecting a subset of users attempting to access their mailboxes via Exchange Online, whether through Outlook on desktop, mobile devices, or the web. The root cause has been traced to a segment of the backend infrastructure, and recovery efforts are actively underway.

Initial remediation steps have already begun, and early indicators suggest gradual improvement. The engineering team is closely monitoring the situation and will expand the fix to remaining systems once stability is confirmed.

Scope of impact: This incident is not limited to any specific region and may affect users globally who rely on Exchange Online connectivity.

• Start time: Thursday, September 11, 2025, at 12:00 PM UTC
• Next update expected by: Friday, September 12, 2025, at 3:30 AM UTC

Microsoft is treating this incident with the highest priority. If you have administrative access, you can track progress via the Microsoft 365 Health dashboard.

No action is required on your part at this time. Once the resolution is fully implemented, mailbox access will be restored automatically.

We appreciate your patience and understanding as Microsoft works diligently to resolve this issue.

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