Outlook Mobile: Push-to-Accept Authentication Error

    Applies to:
  • Legacy SecureAuth IdP
Deployment model:
  • On Premises
  • SecureAuth IdP Version Affected:  All


    When users choose Push Notification as their 2FA while trying to using Outlook on their Mobile Device, it fails after pressing "Accept". The error message they receive may be "An Error in Authentication has Occurred", "Authentication Error", or "Object Reference not set to an instance of an object".


    Cause: ASP.NET does not know that the embedded browser supports EcmaScript v3, so the embedded browser is not trusted or recognized which causes the failure.


    1.  Create a new folder within your SecureAuth realm that is used for Outlook and name it "App_Browsers" -  D:\SecureAuth\SecureAuth#\App_Browsers

         2. Within that folder, create a file named "Outlook.browser" with a .browser file extension.

         3. Include the following inside the file:


    <browser id="Outlook" parentID="Default">


    <userAgent match="Outlook" />



    <capability name="ecmascriptversion" value="3.0" />






    Save the file and retry login using Push Notification as 2FA. The user should be able to login successfully.


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