I am currently working on a function app and would like to understand more on the built in authentication using Microsoft as the identity provider. I have created an app registration as per this

CodePudding user response：

For your function app, in the Authentication blade, check what is being displayed for Issuer Url for the Microsoft Authentication provider. If you have configured to authenticate users from your organization's Azure AD, then that will be the tenant ID, and the url should be login.microsoftonline.com/<guid of tenant>. It depends on what you chose for your target audience, refer here.