Office.js error - API is not supported in this platform

Piyumi Perera 91 Reputation points


I have developed an outlook add-in which follow Single Sign On (SSO) as authorization model. I am following guidelines provided in here to configure SSO. I have tested it on Outlook 2016 desktop, OWA. But I am getting following error in Outlook desktop build version 16.0.10386.20017.

API is not supported in this platform (Converted from French to English)


I have added following two as authorized client applications.


I need a help from experts to understand what has happened.

JavaScript API
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An Office service that supports add-ins to interact with objects in Office client applications.
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Microsoft Graph Identity API
Microsoft Graph Identity API
A Microsoft API to access Azure Active Directory (Azure AD) resources to enable scenarios like managing administrator (directory) roles, inviting external users to an organization, and, if you are a Cloud Solution Provider (CSP), managing your customer's data.
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Office Development
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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.
2,204 questions
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Accepted answer
  1. Matt Geimer 76 Reputation points

    The reason it isn't working is that Outlook version isn't supported for using the SSO API. You can find supported versions along with the Identity 1.3 API requirement set. In the case of clients being used with add-ins that use SSO that aren't supported, you can utilize a backup method to authenticate users such as the dialog API and MSAL. When getAccessToken() returns the not supported error you can launch your fallback method to authenticate, get a token, and continue.

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