Microsoft 365 Alert : Service degradation – Exchange Online – Users are repeatedly prompted to download “TokenFactoryIframe” when browsing Outlook on the web via Safari on Mac OS – RESOLVED

05/05/2022 09:47:00 AM (BST)

Issue Reported : 02/05/2022  08:57:00 PM UTC

Microsoft Reference : EX375556  

NHSmail Reference : INC28805683

Issue Status : RESTORED

Issue Description : Users are repeatedly prompted to download “TokenFactoryIframe” when browsing Outlook on the web via Safari on Mac OS.

More info : Users report seeing the same download prompt when accessing office.com as well from the Safari browser.

Scope of impact : This issue affected all users leveraging the Safari browser to access Outlook on the web.

Final Update : 06/05/2022 09:24:00 AM – Microsoft’s fix addressing the impacting property mismatch has successfully completed deployment. They have confirmed via service telemetry and through additional reports from some formerly affected users that impact is remediated for all users.

Root cause : A recent update to our Office User Experience (UX) changed a parameter from “conditional” to “required” in order to sync client-side and service-side properties. However, the Outlook on the web service didn’t receive the same change as intended, resulting in a property mismatch and repeated “TokenFactoryIFrame” download prompts.

Next steps : Microsoft are assessing our Office User Experience update validation methodology to isolate and remediate potential property mismatches prior to future deployment.

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