Unable to use SSO when browser blocks third-party cookies in outlook add-in

[HugoLd]

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I created an add-in (using the new integrated spam reporting feature) on which I need SSO to work.

I configured properly the WebApplicationInfo and everything works fine on most people's browser, but after some clients complaints, I investigated and found out some browsers block third-party cookies by default(brave, but chrome plan to do it by default as well).
I'm able to reproduce the problem in chrome when I disable manually the third-party cookies,

As chrome is the main browser and plan to disable them by default, I'm worried about the future of this add-in.

Any workaround ?

Your Environment

Any browser with disabled third party cookies

Expected behavior

Have a way to manage SSO on browser refusing third-party cookies

Current behavior

Authentication doesn't work

Steps to reproduce

Disable third party cookies in the browser
Setup an outlook add-in with WebApplicationInfo and call Office.auth.getAccessToken

Context

Some of my users are unable to use the add-in(I can't make them enable third-party manually), but likely in the next years no users will be able to use it anymore.
Could be link to this ticket : #2993

Useful logs

[shighosh-msft]

Hi @HugoLd, to address the issue with SSO with 3P cookie blocking in the browser, please refer to the following article: https://devblogs.microsoft.com/identity/managed-devices-for-blocked-third-party-cookies/

Also, a long-term solution you can also explore nested app authentication (NAA) - the details are here: https://learn.microsoft.com/en-us/office/dev/add-ins/develop/enable-nested-app-authentication-in-your-add-in