Let's Encrypt confirmation on IIS not working

Question

I'm trying to use the Certify SSL Manager to configure SSL certificates from Let's Encrypt on my IIS server, but it fails during the check.

https://dev.mywebsite.com/.well-known/acme-challenge/configcheck/

This works:
https://dev.mywebsite.com/well-known/acme-challenge/configcheck https://dev.mywebsite.com/.well-known/acme-challenge/test.txt

So I assumed it's the . before well-known. But the fact that test.txt works confuses me.

I've already configured the directory according to this discussion: https://github.com/ebekker/ACMESharp/issues/15

I have a bunch of rewrite stuff in my web.config, but even if I remove that section completely, it still fails.

Answer 1

Perhaps check if the acme-challenge web.config contains a conflict within the handler section. Do so by opening IIS manager, find the acme-challenge folder en double click the handler mapping icon. In my case, this resulted in an error.

The problem I ran into with the default web.config in the acme-challenge folder was that the applicationhost.config contained:

<section name="handlers" overrideModeDefault="Deny" />

The handlers section in the acme-challenge web.config therefore was not allowed with the result that the challenge failed. In this case the solutions were: Change applicationhost.config line to:

<section name="handlers" overrideModeDefault="Allow" />

Or ... Remove the handlers setting from the web.config in acme-challenge folder.

The applicationhost.config can be found here: c:\windows\system32\inetsrv\config