Microsoft Shares Fix for Exchange Online EWS Issues
EWS Restrictions and User Impact
Microsoft has officially begun restricting the Exchange Web Services (EWS) interface within the Exchange Online environment. This change impacts numerous applications, including older versions of Outlook, Apple Mail on macOS, and various calendar synchronisation tools. Users relying on applications that use this protocol are already encountering errors, such as service unavailability or persistent authentication prompts.
EWS acts as an API, allowing applications to access mailbox data, including emails, meetings, and contacts. According to the company's roadmap, this feature will be blocked by default starting 1 October 2026. However, administrators retain the ability to temporarily restore access until 1 April 2027, at which point the service will be permanently retired.
How to Restore EWS Access
If your organisation’s applications have stopped working, Microsoft offers two primary solutions for administrators. The first option is to use the Microsoft 365 Admin Center. Within the Baseline Security Mode settings, you must uncheck the option labeled "Block your entire organization from using EWS," which will immediately restore service functionality.
An alternative method involves using Exchange Online PowerShell. By executing the command "Set-OrganizationConfig -EWSEnabled $true," EWS support will be restored for four hours. It is important to note that these measures are temporary. Microsoft has clarified that this process does not affect on-premises Exchange Servers, where EWS will continue to operate.
Transitioning to Modern Standards
In the long term, Microsoft is urging developers and IT specialists to transition to the Microsoft Graph API. The Graph API fully covers the capabilities of EWS while ensuring modern security standards. If you are using third-party applications, it is recommended that you request updated versions from the manufacturers that no longer rely on the legacy protocol.
This change has been long anticipated; Microsoft ceased functional updates for EWS in 2018 and officially confirmed its full retirement plan in 2023. For organisations using Microsoft 365 enterprise solutions, it is essential to audit systems in advance to ensure that application functionality remains uninterrupted by the April 2027 deadline.