Is anyone else in the EU West region having troubles with EWS in Exchange Online since Wednesday? We have several systems that still rely on EWS because the software vendor hasn't updated to MS Graph yet. Since Wednesday, about half of our mailboxes are returning an HTTP 403 error, and there's no difference in configuration or permissions compared to the mailboxes that are working fine.
4 Answers
Those 403 errors with identical configurations usually mean there’s a backend issue or some sort of policy rollout happening on Microsoft’s end. It might be worth checking the service health dashboard for any alerts or recent changes in auth policies that could be affecting us.
I think I might have accidentally triggered the outage myself by running a get-mailbox command in PowerShell. Oops! Might be worth confirming if anyone else had similar actions around that time.
Same here, my Synology Active Backup for 365 has been failing since Wednesday with those 403 errors. I tried creating a new application in Entraid, but no luck. Seems like a widespread issue on Microsoft's side.
I heard that Microsoft might start doing these random 'scream tests' before the final switch to MS Graph in October 2026. If you set your tenant's EWSEnabled setting to True, you should avoid getting hit by any of those tests. They’ll also keep admins updated with monthly posts on EWS usage, so watch for that!
For reference, they mentioned that these temporary tests could help uncover hidden dependencies with EWS before they toggle it off completely. Here’s the link for more details: [Microsoft Tech Community](https://techcommunity.microsoft.com/blog/exchange/exchange-online-ews-your-time-is-almost-up/4492361).
That's good to know! I hope they provide more clarity soon since a lot of us depend on EWS.