1-5-B2C Returning 'Unauthorized_client' error

[kenshinee]

Microsoft.Identity.Web version

2.13.0

Web app sign-in

1-WebApp-OIDC/1-5-B2C

Web API (call Graph or downstream APIs)

Not applicable

Deploy to Azure

Not applicable

Auth Z

Not applicable

Description

I configure a B2C and a Web App as described here https://learn.microsoft.com/en-us/azure/active-directory-b2c/configure-authentication-sample-web-app?tabs=visual-studio.

I backtracked a few times to make sure I am using the correct setting. However, when I run the web app, it loads. After selecting "Sing Up/In" or "Claims" on the menu, it shows the following error "Message contains error: 'unauthorized_client', error_description: 'AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow."

I must be missing out something which I couldn't get my head around.

Reproduction steps

1. Configure B2C,
2. Setup User Flows
3. Register App as described https://learn.microsoft.com/en-us/azure/active-directory-b2c/configure-authentication-sample-web-app?tabs=visual-studio
4. Configure Web App as described https://github.com/Azure-Samples/active-directory-aspnetcore-webapp-openidconnect-v2
5. Run the app
6. Home page loads successfully. When select "Claim" or "sign In", error is returned.

Error message

"Message contains error: 'unauthorized_client', error_description: 'AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow."

Id Web logs

No response

Relevant code snippets

Solution 1-5-B2C

Regression

No response

Expected behavior

Redirect to B2C login

[kenshinee]

I resolved this be adding "Access Tokens" to the App's authentication. The setup mentioned this was not required. However, somehow switching it on resolved my problem.

[phenixita]

I have the same issue.

I don't know if it's "correct" to enable Access tokens.

I want only to sing-in users and I'd like to enable only ID tokens.

This setting is working fine if I register an application in Azure Active Directory "standard".