I've created the .well-known\acme-challenge directories, checked their permissions, and can access a test file I placed inside:
https://test-engine.eleutian.com/.well-known/acme-challenge/test.txt
My domain is: test-engine.eleutian.com
I ran this command: certbot certonly --webroot
It produced this output:
Domain: test-engine.eleutian.com
Type: unauthorized
Detail: Invalid response from
https://test-engine.eleutian.com/.well-known/acme-challenge/25Z6N7xKb1SSA4Mg5KoCFKrVejyJe1FOrdSEVNkpo8U
[2600:9000:21eb:6800:19:266c:200:93a1]: " \n<html
xmlns="http"
My web server is: IIS 10.0.14393.0
The operating system my web server runs on is: Windows Server 2016
My hosting provider is: AWS
I can login to a root shell on my machine: Yes
I'm using a control panel to manage my site: no
The version of my client is: 1.5.0