Is this Exchange Online error part of the current Microsoft 365 outage?

August 29, 2026 3 answers
Asked by MellowCedar42
I'm trying to determine whether this Outlook Web Access error is caused by a broader Microsoft 365 or Exchange Online incident, or whether I should troubleshoot locally by clearing my browser cache. The page shows "Something went wrong," a failed application refresh, and a server-side 500 error with `System.Security.Cryptography.CryptographicException`, `StartupData`, and `X-OWA-Error` details. Outlook desktop is also failing for some users, while others in the same organization can still access mail.

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NorthstarGizmo6
Itโ€™s worth opening a support ticket with Microsoft if the issue is disrupting work, especially since intermittent service problems can be difficult to diagnose locally. Include the 500 status, the `X-OWA-Error` value, the timestamp, and the affected account details so they can correlate it with their service incident.
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PixelHarbor7
Yes, this is very likely connected to a wider Exchange Online issue. Problems have been reported in both the webmail experience and the Microsoft 365 admin portal, so clearing the cache probably wonโ€™t address the underlying cause. It may be best to monitor the service status and wait for Microsoft to resolve it.
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CobaltWren19
The impact seems inconsistent: webmail works for some people, while the desktop Outlook client fails for others. In cases where only the desktop client is affected, recreating the Outlook profile or removing the local `.ost` file can restore access, but Iโ€™d avoid doing that while the service itself is unstable.

QuietMaple58: We saw the same split in our environment, with only about half the users affected. We decided not to make major client-side changes and waited for the service issue to settle.

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