Outlook Web Add-in MS-Edge WebView WWAHost Issue


Outlook web add-ins are launched every time in a new process instance of MS-Edge WebView browser (WWAHost.exe) losing the Azure AD Authentication SSO session cookies so that users are repeatedly asked to login

Environment and Application Background:
• An Outlook web add-in featuring an ASP.NET Core website using Azure AD OpenID connect SSO AuthCode flow authentication using ADAL .NET Core library
BEFORE: Azure AD Login SSO Sessions used to work and retain login sessions across multiple add-in launches When we were in Windows 1809 and Outlook client (Microsoft 365 Apps), because it used Internet Explorer 11 browser for launching web add-ins
NOW ISSUE: We recently upgraded to Windows 1909 and Outlook Version 2008 Build 13127 (Microsoft 365 Apps for enterprise), the Azure AD SSO login sessions are not maintained across add-in launches, causing the user to login repeatedly

On analysis, as per the Browsers used by Office Add-ins, Outlook add-ins are now launched using MS Edge WebView embedded browser related to process WWAHost.exe, since it creates new process for WWAHost.exe every time add-in is launched causing the SSO session cookies deleted/not visible across WWAHost.exe process instances, hence users are asked to repeatedly login.

Is there a way to Launch the Outlook add-in in the same process instance of WWAHost.exe? as opposed to different process instance everytime addin is launched?

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Office: A suite of Microsoft productivity software that supports common business tasks, including word processing, email, presentations, and data management and analysis.Development: The process of researching, productizing, and refining new or existing technologies.
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  1. mickog 106 Reputation points

    We are having very similar issues with SSO and Windows 10 upgrade. Causing the plugin to open a separate browser for the user to sign in. Wondering did you come to any solution?

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