Microsoft blocked EWS in Exchange Online on 1 October. Your mail integration may be dead.
By Lior AharonovFounder, 7IT Solutions ·
What happened
Microsoft published guidance on 22 October 2026 for apps that broke after Exchange Web Services was blocked by default in Exchange Online on 1 October. Admins can switch EWS back on with Set-OrganizationConfig -EWSEnabled $true, which Microsoft says takes effect within 4 hours. EWS shuts down for good on 1 April 2027, per BleepingComputer.
Why it matters
If your product reads or sends mail through a customer's Microsoft 365, it may be failing right now with a password prompt that never ends. The switch is a patch on a clock. After April it stops working.
What to do
Find every integration that calls EWS and move it to Microsoft Graph, which Microsoft recommends. Until then, ask affected customers' admins to re-enable EWS.
A temporary switch has an expiry date. Build for the date, not the switch.
Lior Aharonov · my takeSources
| Microsoft shares how to fix broken Exchange Online EWS apps (BleepingComputer) | bleepingcomputer.com |
| Retirement of Exchange Web Services in Exchange Online (Microsoft 365 Developer Blog) | devblogs.microsoft.com |
Researched with AI tools; every fact is checked against the linked sources.