Acme-challenge timing out

I can manually open the acme-challenge link (in the short time it is available), via the web site. This is the first of 4 servers that I use certbot with the others are not yet due for renewal.

My domain is:
I ran this command:
certbot certonly --dry-run -v --webroot -w /var/www/html -d

It produced this output:
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator webroot, Installer None

An RSA certificate named already exists. Do you want to update
its key type to ECDSA?

(U)pdate key type/(K)eep existing key type: u
Simulating renewal of an existing certificate for
Performing the following challenges:
http-01 challenge for
Using the webroot path /var/www/html for all unmatched domains.
Waiting for verification...
Challenge failed for domain
http-01 challenge for

Certbot failed to authenticate some domains (authenticator: webroot). The Certificate Authority reported these problems:
Type: connection
Detail: Fetching Timeout during connect (likely firewall problem)

Hint: The Certificate Authority failed to download the temporary challenge files created by Certbot. Ensure that the listed domains serve their content from the provided --webroot-path/-w and that files created there can be downloaded from the internet.

Cleaning up challenges
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):
nginx version: nginx/1.18.0 (Ubuntu)

The operating system my web server runs on is (include version):
Ubuntu 22.04.2 LTS

My hosting provider, if applicable, is: N/A

I can login to a root shell on my machine (yes or no, or I don't know):

I'm using a control panel to manage my site (no, or provide the name and version of the control panel):

The version of my client is (e.g. output of certbot --version or certbot-auto --version if you're using Certbot)
certbot 2.5.0

Hi, and welcome to the LE community forum :slight_smile:

Like LE, I can't reach that site either:

curl -Ii
curl: (56) Recv failure: Connection reset by peer

I should have listened to the error. There was a firewall in the router turned on by my colleague. Because the web mail site was under attack. I should add the lets encrypt servers to the exceptions.

1 Like

That won't be possible.
FAQ - Let's Encrypt (


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