Can't get a certificate through certbot

Please fill out the fields below so we can help you better. Note: you must provide your domain name to get help. Domain names for issued certificates are all made public in Certificate Transparency logs (e.g. |, so withholding your domain name here does not increase secrecy, but only makes it harder for us to provide help.

My domain is:

I ran this command: sudo certbot --apache

It produced this output:

Saving debug log to /var/log/letsencrypt/letsencrypt.log

Which names would you like to activate HTTPS for?


Select the appropriate numbers separated by commas and/or spaces, or leave input
blank to select all options shown (Enter 'c' to cancel): 1
Requesting a certificate for

Certbot failed to authenticate some domains (authenticator: apache). The Certificate Authority reported these problems:
Type: unauthorized
Detail: Invalid response from Best []: "\n\n\nBest<"

Hint: The Certificate Authority failed to verify the temporary Apache configuration changes made by Certbot. Ensure that the listed domains point to this Apache server and that it is accessible from the internet.

Some challenges have failed.
Ask for help or search for solutions at See the logfile /var/log/letsencrypt/letsencrypt.log or re-run Certbot with -v for more details.

My web server is (include version): Apache 2.4.41

The operating system my web server runs on is (include version): Ubuntu 20.04

My hosting provider, if applicable, is:I am using my own computer

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): 1.20.0

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Your site is using some kind of <iframe> redirect service to your IP address on port 8787. This is not compatible with Let's Encrypts http-01 challenge type, which is used by the --apache plugin.

It looks like your port 80 on the IP address is working too? So why not update your ddns DNS to point directly to your IP address and just use port 80? That would at least be compatible with Let's Encrypts http-01 challenge. And those <iframe> things are really not the best thing to implement anyway, especially if there's not a good reason to do so.


Just something I noticed:

You show HTTP vhosts for both names; but both names don't have IP addresses.

*** [DNS] can't find Non-existent domain

The problem is that my ISP is blocking any port 80 traffic so I was using NOIP to perform a redirect to 8787 so it would pass through then my router changes it back to port 80. Basically, I think there is no way I can get around this.

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Use DNS-01 validation.

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Is? Or was? Because I'm getting the same response on port 8787 or on port 80? (On IP address obviously.) Nothing blocked it seems..


My ISP blocks port 80. I use No-Ip as my DNS to send all port 80 traffic to port 8787 and then I set my router to send all external traffic on 8787 to the internal port of 80 for my webserver. I have used the DNS-01 validation and successfully obtained an SSL certificate, but I am still getting warnings that my website is not secure.

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@Wendell You need to use and this requires port 443 to be open. It is showing as 'closed':

22/tcp  open   ssh
80/tcp  open   http
443/tcp closed https

Perhaps I misunderstand your problem but these should both work. Ideally, your http site redirects to https but it isn't. And, it won't work anyway until you get the curl for https working:

[TEST]> curl -I

HTTP/1.1 200 Found
Date: Tue, 26 Oct 2021 14:15:03 GMT
Server: Apache
Content-Type: text/html

[TEST]> curl -I

curl: (7) Failed to connect to port 443: Connection refused

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