[Azure AD B2C] AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow

[kengaderdus]

Microsoft.Identity.Web version

2.15.2

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

After I hit sign-in button, I see this error:

AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow. The app worked as expected 6 months ago.

Reproduction steps

Use the steps in this article: https://learn.microsoft.com/en-us/azure/active-directory-b2c/configure-authentication-sample-web-app?tabs=visual-studio

Error message

AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow

Id Web logs

info: Microsoft.AspNetCore.Mvc.ChallengeResult[1]
Executing ChallengeResult with authentication schemes (OpenIdConnect).
info: Microsoft.AspNetCore.Authentication.OpenIdConnect.OpenIdConnectHandler[12]
AuthenticationScheme: OpenIdConnect was challenged.
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[105]
Executed action Microsoft.Identity.Web.UI.Areas.MicrosoftIdentity.Controllers.AccountController.SignIn (Microsoft.Identity.Web.UI) in 0.6875ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
Executed endpoint 'Microsoft.Identity.Web.UI.Areas.MicrosoftIdentity.Controllers.AccountController.SignIn (Microsoft.Identity.Web.UI)'
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
Request finished HTTP/2 GET https://localhost:44316/MicrosoftIdentity/Account/SignIn? - - - 302 0 - 1.0263ms
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
Request starting HTTP/2 POST https://localhost:44316/signin-oidc application/x-www-form-urlencoded 561
fail: Microsoft.AspNetCore.Authentication.OpenIdConnect.OpenIdConnectHandler[12]
Message contains error: 'unauthorized_client', error_description: 'AADB2C90057: The provided application is not configured to allow the 'OAuth' Implicit flow.
Correlation ID: 8927928d-fd2d-4d4c-a512-585c459d745e
Timestamp: 2023-11-08 12:40:17Z
', error_uri: 'error_uri is null'

Relevant code snippets

Refer to the code sample.

Regression

2.15.2

Expected behavior

I expect to successfully sign in or sign up, then obtain an ID token.

[markjerz]

Did you manage to fix this?

[SemperFu]

Having this same issue. I can see the response type in dev tools is id_token. I have enabled ID Tokens under app registration in my b2c but same error.