Azure AD B2C Social Signups Failing - azure

Question

I'm trying to get an AspNet Core 2.1 website to authenticate via Azure AD B2C. I've configured the Google and Microsoft Account signups in my tenant per the online instructions I found (e.g., this for Google).
But neither signup/signin option works. Links to them display on the default Azure AD B2C login page, but clicking the links triggers an error:
for Google, it causes a redirect_uri_mismatch error
for Microsoft Account, it returns a "we're experiencing technical
difficulties" error page, which has persisted for more than 24 hours,
so I doubt there's been any kind of outage
This is all occurring in a development environment, so I'm not using a publicly-registered domain (e.g., the reply uris all point back to localhost). Is that possibly the problem? If so, how do I set up the development environment correctly?
Additional Info
I solved the problem with the google identity provider.
But I'm still getting the same error with the Microsoft Account provider. However, I just noticed that there's an error message buried within the URL for the error page which doesn't get displayed on the page itself:
error=invalid_request&error_description=The+provided+value+for+the+input+parameter+'redirect_uri'+is+not+valid.+The+expected+value+is+'https://login.live.com/oauth20_desktop.srf'+or+a+URL+which+matches+the+redirect+URI+registered+for+this+client+application.
The first suggestion in the error message -- targeting login.live.com -- doesn't work. The Microsoft Application Portal complains about a domain mismatch.
But I don't see how to apply the second suggestion, because I don't know where the redirect_uri is generated by/stored in my web app (i.e., I defined the redirect uri in the Microsoft Application Portal, but I don't see a corresponding configuration parameter in my webapp).

Answer 1

Ensure that you are registering the same base reply urls in your social providers, that your application is calling from B2C.
For example:
You if your app calls https://contoso.b2clogin.com/contoso.onmicrosoft.com/oauth2/v2.0/authorize then the reply url in your social provider should be https://contoso.b2clogin.com/contoso.onmicrosoft.com/oauth2/authresp
However, some app examples call https://contoso.b2clogin.com/te/contoso.onmicrosoft.com/oauth2/v2.0/authorize (notice the "te") so you therefore need to add a reply URL of https://contoso.b2clogin.com/te/contoso.onmicrosoft.com/oauth2/authresp
I generally add both.

Answer 2

Are you able to sign-up with the local email account at first?, if not this link
https://learn.microsoft.com/en-us/azure/active-directory-b2c/active-directory-b2c-tutorials-web-app
would be helpful which has a sample web app and the steps, once you are able to sing-up and authenticate , you can add identity providers as Google, Microsoft, Facebook etc., and then you can edit the sign-up or sign-in policies and add the identity providers of Google, Microsoft etc.,
I hope this helps, cheers!! please let me know if you face any issues
Suraj Revankar

Answer 3

Turns out the documentation I was following for setting up the MicrosoftAccount identity app was incorrect, or I was following the wrong instructions.
Basically, you need to redirect to
https://your-tenant-name.b2clogin.com/your-tenant-name.onmicrosoft.com/oauth2/authresp
not
https://localhost:[port#]/signin-oidc
like the documentation I was originally following suggested.
Check out this question and answer for more details.