MiddlewarePipelineJWTCookie.cs

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    // ... Other middlewares ...
    
    app.UseHttpsRedirection();
    app.UseStaticFiles();
    app.UseSpaStaticFiles();
    app.UseCookiePolicy();

    app.UseJwtCookieMiddleware(app.ApplicationServices.GetService<IAntiforgery>(), Encoding.ASCII.GetBytes("signing key"));

    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");
    });

    app.UseAntiforgeryCookieMiddleware(app.ApplicationServices.GetService<IAntiforgery>());

    app.UseSpa(spa =>
    {
        spa.Options.SourcePath = "ClientApp";

        if (env.IsDevelopment())
        {
            //spa.UseReactDevelopmentServer(npmScript: "start");
            spa.UseProxyToSpaDevelopmentServer("http://localhost:3000");
        }
    });
}