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

if removing the "addDefaultIdentity" from "Startup.cs" does not work for you .

Replace services.AddDefaultIdentity<ApplicationUser> to AddIdentity<ApplicationUser, IdentityRole>

Code snippet

  /*
            services.AddIdentity<ApplicationUser, IdentityRole>(options => options.SignIn.RequireConfirmedAccount = true)
                .AddEntityFrameworkStores<ApplicationDbContext>();
            */
            
            services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
                .AddEntityFrameworkStores<ApplicationDbContext>();