Hi,
Can you please help me with the following problem:
I have installed Exchange 2016 on my server en follow this tutorial for install a certificate.
However it gives me the error Authorization result: invalid (see below)
I have read that duckdns needs a TXT record which can be read by letsencrypt.
So I tried to create a TXT record but where can I get the txt / key that i have to fill in where i set the question marks below?
https://www.duckdns.org/update?domains={mail,autodiscover}&token={MyToken Number}&txt={???}[&verbose=true]
Thanks a lot if you can help me.
it gives me a headache…
My domain is:mail.dhavenaar.nl autodiscover.dhavenaar.nl (dhavenaar.duckdns.org)
I ran this command: WACS.EXE as administrator
It produced this output:
[mail.dhavenaar.nl] Authorizing…
[mail.dhavenaar.nl] Authorizing using http-01 validation (SelfHosting)
[mail.dhavenaar.nl] Authorization result: invalid
[mail.dhavenaar.nl] {
“type”: “urn:ietf:params:acme:error:unauthorized”,
“detail”: "Invalid response from http://mail.dhavenaar.nl/.well-known/acme-challenge/mR_PwpzdycC9KNKHnYkToD_7UrZvMYrni2hdch0vGkc [77.170.52.41]: “\r\n<html xmlns=\“http””,
“status”: 403
My web server is (include version): No webserver, Exchange 2016
The operating system my web server runs on is (include version): Windows server 2016
My hosting provider, if applicable, is: KPN
I can login to a root shell on my machine (yes or no, or I don’t know): Yes
I’m using a control panel to manage my site (no, or provide the name and version of the control panel): No
The version of my client is (e.g. output of certbot --version or certbot-auto --version if you’re using Certbot):

