It requires Microsoft Graph Application registration. Start at the Microsoft azure portal:\\
[https://azure.microsoft.com/en-us/features/azure-portal/]\\
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__Application registration__: Go to the App registrations and click on New registration:\\
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[attachments|SMTP Microsoft Graph XOAUTH 2 Integration/new_registration.png]\\
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Name it. Select __Single-page Application__ as platform. The redirect url must ends with :__WebInterface/login.html__. Then click on register.\\
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[CrushOAuth/app_reg_config.png]\\
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Make sure that MSAL.js 2.0, Implicit grant (Access Token, ID Token) grant types are permitted.\\ 
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[CrushOAuth/app_reg_auth_config.png]\\
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Get Client Id and Tenant Id from App registration -> Overview.\\
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[MicrosoftMails/client_id.png]\\
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Go to the __Preferences__-> __Ip/Servers__ and select the __HTTP or HTTPS__ port item(__OAuth Sign in__  Tab) where you want to enable the __Microsoft Sing-In__ button. Check the __"Enable Microsoft Sign in"__ flag and provide the __Client ID__ and __Tenant ID__ of your App registration(mentioned above).\\
[CrushOAuth/port_item_settings_ms.png]\\
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__Continue on:__ [CrushOAuth]\\
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