AAD B2C Provider not working in next-auth v5

Provider type

Azure Active Directory B2C

Environment

  System:
    OS: Windows 11 10.0.22631
    CPU: (16) x64 12th Gen Intel(R) Core(TM) i5-1240P
    Memory: 854.78 MB / 15.72 GB
  Binaries:
    Node: 20.16.0 - C:\Program Files\nodejs\node.EXE
    npm: 10.8.1 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Edge: Chromium (127.0.2651.98)
    Internet Explorer: 11.0.22621.3527
  npmPackages:
    next: ^15.0.2 => 15.0.2
    next-auth: ^5.0.0-beta.25 => 5.0.0-beta.25
    react: ^19.0.0-rc-7c8e5e7a-20241101 => 19.0.0-rc-fb9a90fa48-20240614

Reproduction URL

I am following basic configuration, please see below

Describe the issue

In previous version of provider, where credentials where provided in following format the authentication worked well

  providers: [AzureADB2C({
    tenantId: process.env.AZURE_AD_B2C_TENANT_NAME,
    clientId: process.env.AZURE_AD_B2C_CLIENT_ID,
    clientSecret: process.env.AZURE_AD_B2C_CLIENT_SECRET,
    primaryUserFlow: process.env.AZURE_AD_B2C_PRIMARY_USER_FLOW,
    authorization: { params: { scope: "offline_access openid" } },
  })

However once upgraded to Next.auth v5 where issuer is needed instead of tenantId and primaryUserFlow, I am getting server error, stating: There is a problem with the server configuration. Currently I have following configuration, which is not working:

   providers: [AzureADB2C({
      clientId: process.env.AZURE_AD_B2C_CLIENT_ID,
      clientSecret: process.env.AZURE_AD_B2C_CLIENT_SECRET,
      issuer: process.env.AZURE_AD_B2C_ISSUER,    
      authorization: { params: { scope: `offline_access openid https://${process.env.AZURE_AD_B2C_TENANT_NAME}.onmicrosoft.com/api/invoke` } },
    })

Documentation also doesn't state issuer format to be used for AAD B2C. I use following: https://{mytenantname}.b2clogin.com/{mytenantname}.onmicrosoft.com/oauth2/v2.0/authorize?p=B2C_1A_SIGNUP_SIGNIN where B2C_1A_SIGNUP_SIGNIN is default policy I use.

How to reproduce

Create minimal setup with AAD B2C provider, and it will cast Configuration error

Expected behavior

Expected behavior is that v5 will continue working with AAD B2C

We could not detect a valid reproduction link. Make sure to follow the bug report template carefully.

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nextauthjs / next-auth