Set web.config for letsencrypt - Certify with Asp.NET Core and Angular 2 (Javascript-services)

Question

I am trying to install letsencrypt certificate with Certify, but I get error, which (I think) has nothing to do with Certify. Problem is how my web.config is configured for

Answer 1

In my case, the problem was I forgot to remove App_Offline.htm while issuing the request. After removing it, the problem disappeared.