How to enable forms authentication programmatically?

Question

So, my attempts are:
1)Site.WebApplication.IisSettings[currentZone].AuthenticationMode = System.Web.Configuration.AuthenticationMode.Forms; Site.WebApplication.IisSettings[currentZone].MembershipProvider = "MyMembershipProvider"; Site.WebApplication.IisSettings[currentZone].EnableClientIntegration = true; Site.WebApplication.IisSettings[currentZone].AllowAnonymous = false; Site.WebApplication.Update();
2) Change web.config (authentication, impersonation, login page url).

But then I cannot authenticate any user. Please help!

Response of the request to /_vti_bin/authentication.asmx is 401 Unauthorized. And IIS settings are strange -

Answer 1

Issue was solved. It was necessary to install all updates for operation system.