“The requested web method is unavailable to this caller or application”
The endpoint answered, and it refused the operation for this caller. If it started recently and nothing in your code changed, the first thing to read is the tenant's EWS posture, not your code.
- Blank
EwsEnablednever decided. Microsoft's documentation says it changes this to$falseon October 1, 2026 for any tenant that has not explicitly set$true. - True, no listFrom October 2026,
Trueon its own no longer permits unrestricted EWS access. Only allow-listed application IDs can call EWS. - FalseEWS is off org-wide. Every EWS call in every application in this tenant fails, and no per-mailbox setting overrides it.
- CaveatThis fault string is a documented EWS access-denied error and it is the shape a blocked caller gets. We have not found a Microsoft source stating which exact fault the October 1, 2026 disablement returns.
Get-OrganizationConfig -RetrieveEwsOperationAccessPolicy | Format-List EwsEnabled, EwsAllowedAppIDs | deadlinescan tenant
Parsed locally, nothing sent anywhere. What each verdict means. Allow-listing buys time and nothing else: allow-listed applications keep working until March 31, 2027, and April 1, 2027 is the hard shutdown with no exceptions and no re-enablement.
A finding count of zero means no affected call sites were FOUND — not that you're unaffected.
Scan your code
Free, local, one command. Flags the sites with no Graph equivalent.
Get the scannerGet the scanner: email [email protected] and you'll get the source and a Windows binary by reply — the public repository is being prepared.
Set-OrganizationConfig -EwsEnabled:$true
Set-OrganizationConfig -EwsAllowedAppIDs "<comma-separated Entra app client IDs>"