Cant create proper OpenID Connect configuration endpoint (v2) - asp.net-mvc

Question

I want to have an application in azure (simple asp.net mvc application) that keeps users in azure, I want to have that done by azure b2c.
I registered application in azure and put all configurations into appsettings.json what I notice is that the url generated by application does not match the one from azure:
Here's from application:
'https://isthereanynewscodeblast.b2clogin.com/isthereanynewscodeblast.onmicrosoft.com/B2C_1_eclaims_login/v2.0/.well-known/openid-configuration'
Here's from B2C:
'https://isthereanynewscodeblast.b2clogin.com/isthereanynewscodeblast.onmicrosoft.com//v2.0/.well-known/openid-configuration'
Similar but not the same. What I have found is that the url is being generated by AzureADB2COpenIdConnectOptionsConfiguration in this method:
internal static string BuildAuthority(AzureADB2COptions AzureADB2COptions)
{
var baseUri = new Uri(AzureADB2COptions.Instance);
var pathBase = baseUri.PathAndQuery.TrimEnd('/');
var domain = AzureADB2COptions.Domain;
var policy = AzureADB2COptions.DefaultPolicy;
return new Uri(baseUri, new PathString($"{pathBase}/{domain}/{policy}/v2.0")).ToString();
}
And here's my .json
"AzureAdB2C": {
"Instance": "https://isthereanynewscodeblast.b2clogin.com",
"Domain": "isthereanynewscodeblast.onmicrosoft.com",
"ClientId": "guid-of-client",
"CallbackPath": "/signin-oidc",
"SignUpSignInPolicyId": "B2C_1_eclaims_login ",
"ResetPasswordPolicyId": "B2C_1_eclaims_reset",
"EditProfilePolicyId": "B2C_1_eclaims_edit"
},
Which does not match the one from AAD :(
Code is from a nuget: Microsoft.AspNetCore.Authorization
It's not protected nor virtual, so I don't see any option to override it.
So my questions are:
is there a way to handle this somehow, so that application can communicate with azure
is there other way to register app, easy like this:
services.AddAuthentication(AzureADB2CDefaults.AuthenticationScheme)
.AddAzureADB2C(options =>
{
Configuration.Bind("AzureAdB2C", options);
});
//EDIT:
Here's manifest from application registration:
{
"id": "438a430b-4e80-4c6c-8f45-dfca460b2e03",
"acceptMappedClaims": null,
"accessTokenAcceptedVersion": 2,
"addIns": [],
"allowPublicClient": null,
"appId": "44234136-6eee-431f-98ea-668343d7a3fd",
"appRoles": [],
"oauth2AllowUrlPathMatching": false,
"createdDateTime": "2020-08-18T22:32:28Z",
"groupMembershipClaims": null,
"identifierUris": [],
"informationalUrls": {
"termsOfService": null,
"support": null,
"privacy": null,
"marketing": null
},
"keyCredentials": [],
"knownClientApplications": [],
"logoUrl": null,
"logoutUrl": null,
"name": "user-log-test",
"oauth2AllowIdTokenImplicitFlow": false,
"oauth2AllowImplicitFlow": false,
"oauth2Permissions": [],
"oauth2RequirePostResponse": false,
"optionalClaims": null,
"orgRestrictions": [],
"parentalControlSettings": {
"countriesBlockedForMinors": [],
"legalAgeGroupRule": "Allow"
},
"passwordCredentials": [],
"preAuthorizedApplications": [],
"publisherDomain": "isthereanynewscodeblast.onmicrosoft.com",
"replyUrlsWithType": [
{
"url": "https://localhost:44395/signin-oidc",
"type": "Web"
}
],
"requiredResourceAccess": [
{
"resourceAppId": "00000003-0000-0000-c000-000000000000",
"resourceAccess": [
{
"id": "37f7f235-527c-4136-accd-4a02d197296e",
"type": "Scope"
},
{
"id": "7427e0e9-2fba-42fe-b0c0-848c9e6a8182",
"type": "Scope"
}
]
}
],
"samlMetadataUrl": null,
"signInUrl": null,
"signInAudience": "AzureADandPersonalMicrosoftAccount",
"tags": [],
"tokenEncryptionKeyId": null
}

Answer 1

Can you please try using this b2c sample app which will give you an idea how to use b2c points. It comes with pre-configured endpoints (below), which you can replace with your tenant and policy later for testing.
{
"AzureAdB2C": {
"Instance": "https://fabrikamb2c.b2clogin.com",
"ClientId": "90c0fe63-bcf2-44d5-8fb7-b8bbc0b29dc6",
"Domain": "fabrikamb2c.onmicrosoft.com",
"SignedOutCallbackPath": "/signout/B2C_1_susi",
"SignUpSignInPolicyId": "b2c_1_susi",
"ResetPasswordPolicyId": "b2c_1_reset",
"EditProfilePolicyId": "b2c_1_edit_profile"
},
"Logging": {
"LogLevel": {
"Default": "Information",
"Microsoft": "Warning",
"Microsoft.Hosting.Lifetime": "Information"
}
},
"AllowedHosts": "*"
}

Answer 2

I saw your app manifest file and found that you have not enabled implicit flow. Please Select the app and go to Authentication and select ID Tokens and Access Tokens.
I tried on the sample shared by #Razi and it is working fine end-to-end.