Error trying to install the Let's Encrypt certificate.

Hello, I am testing the Virtualmin control panel for the first time and it seems very complete in all the functions that it has.

I have already achieved the installation without errors; and I have configured 2 domains.

The problem I have is that when trying to install the Let’s Encrypt SSL certificate, I always get the following error:

From the Manage Server Configuration option -> SSL Certificate -> Let’s Encrypt

I press the “Request Certificate” button and I get the error:

Requesting a certificate for, from Let’s Encrypt …
… request failed: Web-based validation failed: Failed to request certificate: challenge did not pass: Invalid response from “<! DOCTYPE HTML PUBLIC” - // IETF // DTD HTML 2.0 // EN ">

404 Not Found

Not Found <p "

Honestly I have already searched for information about it but I can not solve it. I hope you can help me.

Thank you in advance, greetings!

betancourt, most of the Let’s-Encrypt fails are due to “DNS not configured correctly for that domain”. Be sure to check that your “” domain is able to be “reached” from the internet. If you are inside a home or office network (behind a NAT) you may need to configure your computer’s IP address as the DMZ machine for that NAT router. Just make sure that someone else “out on the internet” can surf to your domain, that’s what Let’s-Encrypt is trying to do.

Hello, thank you very much for your answer.

The strange thing is that I see my website from the URLs and

However, I still see that error.

What I have seen, is that in intoDNS ( I see certain errors, will that be the cause?

Beforehand thank you very much.