AddIdentity() fails “InvalidOperationException: Scheme already exists: Identity.Application”

Question

I\'m trying to add facebook login to my .NET Core 2.1 site

I\'m following this , guide and more specific, this (for facebook login)

After have adding the lines

Answer 1

This is a change from .Net Core 2.0->2.1, I guess the guide hasnt been updated.

After stumbling upon this SO post I : Removed the lines entire services.AddIdentity()...call (all 3 lines) (but of course kept the AddDefaultIdentity()-call that was there before

Changed back in ApplicationDbContext.cs from

public class ApplicationDbContext : IdentityDbContext

to

public class ApplicationDbContext : IdentityDbContext

... So if your starting out from scratch (new .Net Core 2.1-template), all you have to do is add lines

     services.AddAuthentication().AddFacebook(facebookOptions =>
        {
            facebookOptions.AppId = Configuration["...FacebookLogin:AppId"];
            facebookOptions.AppSecret = Configuration["...FacebookLogin:ClientSecret"];
        });

from the tutorial.

At least this "fix" takes me through so far that the users can register, havent investigated where my "ApplicationUser" went (in case/when I want to add more user-properties)...since there is no reference to it anymore