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

In my case, problem was after add:

services.AddDefaultIdentity().AddRoles()
.AddEntityFrameworkStores();

confliting with below code, in Startup.cs:

services.AddDbContext(options =>
options.UseSqlServer(Configuration.GetConnectionString("MyConnectionString")));
services.AddDefaultIdentity()
.AddEntityFrameworkStores();