Table of Contents
Summary
- EWS access will be blocked for mailboxes without appropriate licenses, specifically for Exchange Online Kiosk, Microsoft 365 and Office 365 F1, and F3 licenses.
- Users with the impacted licenses will no longer be able to access mailboxes via EWS, enforcing existing restrictions that were not previously applied.
- Organizations need to assign new licenses with EWS access, such as Exchange Online Plan 1 or 2, or Microsoft 365 or Office 365 E3 or E5, for affected users.
- Failed EWS access attempts without the right license will return an HTTP 403 response.
- The change has significant impacts on both users and administrators, affecting user experience and requiring administrative action.
Admin Impact: High
User Impact: Low
Release Start: 01 Mar 2026
Release End: 01 Mar 2026
Services: Exchange
Category: Plan for change
Tags: User Adoption, Admin Action
History
12/2/2025 Item Added to Message Center
Microsoft Message
We’re making some changes to Exchange Web Services (EWS).
Starting March 1, 2026, we will start to block EWS access for all mailboxes without license rights to EWS. This is another step in our ongoing commitment to enhance the security and control mechanisms of EWS.
How this will affect your organization
The impacted licenses are:
- Exchange Online Kiosk
- Microsoft 365 and Office 365 F1
- Microsoft 365 and Office 365 F3
As stated in the Service Descriptions, these licenses do not provide access to mailboxes via EWS, but these restrictions were never enforced. With this change, EWS access for users with only these license types will be blocked.
What you need to do to prepare
If you wish these users to continue to use EWS, and your users are licensed with one of these noted above, you’ll need to assign a new license, one containing EWS access rights. For example, you could assign an Exchange Online Plan 1 or 2 license, or a Microsoft 365 or Office 365 E3 or E5 license.
Starting March 1, 2026, requests to use EWS without a suitable license will result in a HTTP 403 response.
Learn more: Update to EWS Access for Kiosk / Frontline Worker Licensed Users