From today, 30 June 2026, Microsoft is enforcing a restriction on Exchange Web Services (EWS) access for certain Microsoft 365 licence types. Organisations on affected plans may find that some email integrations, third-party apps, or older mail client connections stop working without warning.

• What it is: EWS is a legacy protocol used by many apps and integrations to connect to Exchange Online mailboxes. Microsoft has been retiring it in favour of the newer Microsoft Graph API.
• Who is affected: Organisations with users on Exchange Online Kiosk, Microsoft 365 F1, or Microsoft 365/Office 365 F3 licences. After enforcement, requests from these accounts will return an HTTP 403 error.
• What the risk is: Any third-party app, custom integration, or older email client relying on EWS will stop connecting for affected users. This can disrupt workflows — particularly for frontline or field staff on F-tier licences.
• What to do: Check whether any of your users are on an affected licence type. Review what tools and integrations those users rely on. Affected applications will need to be updated to use the Microsoft Graph API. Contact your IT provider if you need help identifying affected accounts or apps.

If you have not already reviewed your licence types and app integrations, we recommend doing so today. Source: Microsoft Partner Center June 2026