解决方法是在启动类中手动将pathbase设置为"/"，即可解决该问题。具体的代码示例如下：

public class Program
{
    public static async Task Main(string[] args)
    {
        var builder = WebAssemblyHostBuilder.CreateDefault(args);
        builder.RootComponents.Add("app");
        builder.Services.AddScoped(sp => new HttpClient
        {
            BaseAddress = new Uri(builder.HostEnvironment.BaseAddress)
        });

        //这里手动将pathbase设置为"/"
        builder.Services.AddApiAuthorization(options =>
        {
            options.ProviderOptions.DefaultAccessTokenScopes.Add("myapi");
            options.AuthenticationPaths.RemoteRegisterPath = "https://localhost:5001/Identity/Account/Register";
            options.AuthenticationPaths.RemoteProfilePath = "https://localhost:5001/Identity/Account/Manage";
            options.UserOptions.RoleClaim = "role";
            options.UserOptions.AuthenticationType = "BlazorAuth";
            options.ProviderOptions.Authority = "https://localhost:5001";
            options.ProviderOptions.ClientId = "BlazorAuth.Client";
            options.ProviderOptions.ResponseType = "code";
            options.ProviderOptions.RedirectUri = $"{builder.HostEnvironment.BaseAddress}authentication/login-callback";
            options.ProviderOptions.PostLogoutRedirectUri = $"{builder.HostEnvironment.BaseAddress}authentication/logout-callback";
            options.ProviderOptions.DefaultScopes.Add("BlazorAuth.ClientAPI");
            options.ProviderOptions.Scope.Add("offline_access");
            options.ProviderOptions.Prompt = "consent";
            options.ProviderOptions.UsePkce = true;
        });

        var host = builder.Build();

        await host.RunAsync();
    }
}