msal.js 2.0 tokenResponse null after loginRedirect

Question

I am developing an Angular 10 app that utilizes Azure B2C for policy and user management. I set up my app registration in Azure Active Directory as a singlepage app without the implicit option checked. I am using msal.js 2.0 @azure/msal-browser to log into B2C and retrieve id and access tokens using code flow. I set up my configuration, created the msal object, defined the redirect promise, then later call loginRedirect with the appropriate user scopes. The page redirects properly.

However, after I sign in the tokenResponse comes back as null. I have tried altering the authority and scopes, but it always comes back as null. How do I get the handleRedirectPromise to return a valid token response?

Here's my code:

    private msalConfig: Msal.Configuration = {
        auth: {
            clientId: xxxx-xx-xx-xx-xxxxx,
            authority: 'https://login.microsoftonline.com/common', 
            redirectUri: 'https://localhost:4200'
        },
        cache: {
            cacheLocation: 'sessionStorage',
            storeAuthStateInCookie: false
        },
    };

    private loginRequest: Msal.RedirectRequest = {
        scopes: ['user.read'],
    };

    const msalInstance = new Msal.PublicClientApplication(this.msalConfig);
    msalInstance
            .handleRedirectPromise()
            .then((tokenResponse: Msal.AuthenticationResult) => {
                let accountObj = null;
                if (tokenResponse !== null) {
                    accountObj = tokenResponse.account;
                    const id_token = tokenResponse.idToken;
                    const access_token = tokenResponse.accessToken;
                    console.log('id_token', id_token);
                    console.log('access_token', access_token);
                }
            })
            .catch(error => {
                authStore.loginError$.next(true);
                console.error(error);
            });

    msalInstance.loginRedirect(this.loginRequest);

Edit:

I have also tried authority: `https://<tenant-name>.b2clogin.com/<tenant-name>.onmicrosoft.com/<policy-name> and https://login.microsoftonline.com/tfp/{tenant}.onmicrosoft.com/B2C_1_SiupIn for the authority in the msalConfig object as well as scopes: ['openid'] in the loginRequest. When I use this I get the following error in the browser when I try to log in:

zone-evergreen.js:1068 GET https://login.microsoftonline.com/common/discovery/instance?api-version=1.1&authorization_endpoint=https://<tenant>.b2clogin.com/<tenant>.onmicrosoft.com/b2c_1_defaultsigninsignup/oauth2/v2.0/authorize 400 (Bad Request)

core.js:4197 ERROR Error: Uncaught (in promise): ClientAuthError: endpoints_resolution_error: Error: could not resolve endpoints. Please check network and try again. Detail: ClientConfigurationError: untrusted_authority: The provided authority is not a trusted authority. Please include this authority in the knownAuthorities config parameter.
ClientAuthError: endpoints_resolution_error: Error: could not resolve endpoints. Please check network and try again. Detail: ClientConfigurationError: untrusted_authority: The provided authority is not a trusted authority. Please include this authority in the knownAuthorities config parameter.

Answer 1

The way you set up the redirect flow seems correct. You first have to call the handleRedirectPromise() (which registers it), and then call the loginRedirect(). At page load handleRedirectPromise() will return null, and after sign-in it should return the token.

There are issues with your configuration, however.

1. You need to designate your domain as a knownAuthority, like:

        auth: {
            clientId: 'xxxx-xx-xx-xx-xxxxx',
            authority: 'https://<tenant-name>.b2clogin.com/<tenant-name>.onmicrosoft.com/<policy-name>', 
            knownAuthorities: ['<your-tenant-name>.b2clogin.com']
            redirectUri: 'https://localhost:4200'
        },

2. User.Read is a MS Graph API scope. You cannot use it with B2C. Only the OIDC scopes are allowed i.e. use openid instead.

See this for more.

Answer 2

The problem was with my angular app. I had my app redirecting the base url to my /home route. So whenever you open the base route the app is redirected. From this route, the request is made. I added the redirect uri for the /home route to my AAD app registration, commented out the redirectUri in my b2c configuration and set navigateToLoginRequestUrl to true.