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.
3 Answers
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 I’d avoid doing that while the service itself is unstable.
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 won’t address the underlying cause. It may be best to monitor the service status and wait for Microsoft to resolve it.
It’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.
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.