ACME server was probably unable to reach

[humblecscoder]

Hello, I read all issues, but still don't understand why this problem appears.
I use IIS 8.5 on Windows Server12 R2. In IIS 8.5 create site with host www.hellohttps.com, but when letsencrypt-win-simple validate key:
The ACME server was probably unable to reach http://www.hellohttps.com/.well-known/acme-challenge/Key, but I can open it in browser.

I have suppose it appears because I don't use hosting, and appel directly ip-address, instead hostname and LE cant reach it. Or am I wrong?
FireWall turned off.
http://80.76.96.182/.well-known/acme-challenge/7IK-bb0WB3v0TjmlycxYqP25TKubKLp8YjVDjrpaoGc
Please answer if possible more detalized. I'm newbie in this.

[humblecscoder]

I already added StaticFile Handler above 3 ExtenssionlessHandler and create web.config in .well-known directory. And still doesn't work

[humblecscoder]

There is domen validation...
I create a domain, and now autorization result valid