Microsoft Shares Fix for Exchange Online Apps Broken by EWS

Microsoft has shared instructions for restoring Exchange Web Services (EWS) access in Exchange Online after some applications stopped working following the API’s retirement changes.

According to Microsoft’s latest guidance, administrators can temporarily restore access to EWS-dependent applications, but the workaround will only remain available until April 1, 2027.

Microsoft began blocking EWS by default on October 1, 2026, as part of its plan to retire the legacy API. The company had previously warned Exchange Online administrators about the upcoming changes.

How to fix Exchange Online applications that stopped working

Microsoft says applications that depend on EWS may encounter connection errors, warnings that the protocol is unavailable, or repeated login prompts.

Administrators can temporarily restore EWS access through the Microsoft 365 Admin Center by navigating to Baseline Security Mode and unchecking the “Block your entire organization from using EWS” option.

Alternatively, administrators can connect to Exchange Online PowerShell and run the following command:

Set-OrganizationConfig -EWSEnabled $true

Microsoft says the PowerShell change should take effect within four hours, allowing affected applications to reconnect.

However, both methods provide temporary access only. Once Microsoft permanently disables EWS on April 1, 2027, administrators will no longer have the option to re-enable it.

Microsoft urges organizations to migrate to Graph API

Microsoft recommends updating applications that still depend on EWS before the final shutdown.

Organizations should move to versions that support the Microsoft Graph API, which provides alternatives for nearly all EWS functionality in most scenarios.

For third-party applications, administrators should contact software vendors to confirm whether newer versions support Microsoft Graph or another compatible integration.

The retirement only affects Exchange Online and Microsoft 365 environments. Organizations running on-premises Exchange Server installations can continue using EWS.

With the permanent shutdown scheduled for April 1, 2027, organizations have just over five months to complete their migration and avoid further disruptions.

Separately, Microsoft recently warned Exchange administrators to patch a critical security vulnerability affecting their environments.