You will need to set up a httpd server in order for the acme-client to work. It is recommended to use openhttpd, click here to find out how to set up openhttpd.

First, copy the /etc/examples/acme-client.conf template:

$ doas cp /etc/examples/acme-client.conf /etc/acme-client.conf

authority letsencrypt {
        api url "https://acme-v02.api.letsencrypt.org/directory"
        account key "/etc/acme/letsencrypt-privkey.pem"
}

authority letsencrypt-staging {
        api url "https://acme-staging.api.letsencrypt.org/directory"
        account key "/etc/acme/letsencrypt-staging-privkey.pem"
}

domain example.com {
        alternative names { secure.example.com }
        domain key "/etc/ssl/private/example.com.key"
        domain full chain certificate "/etc/ssl/example.com.fullchain.pem"
        sign with letsencrypt
}

Replace example.com with your domain. If you didn't use any alternative names, in the past, having:

alternative names { }

would cause issues. So, if you have no alternative names, I recommend you comment that line out as follows:

#        alternative names { secure.example.com }

Now, run acme-client:

$ doas acme-client -Fv example.com

If you run into errors, check to make sure:

• DNS is configured properly.
• The web server is configured properly. You must have a web server in order for the acme-client to work. (Don't be confused here if your web server seems not running in a web browser: the example config redirects all visits to the https port, that may not yet be working yet.)
• You have the proper permissions set on the folders in /var/www/. An example output would be,

$ ls -l /var | grep www
drwxr-xr-x  11 root     daemon     512 Mar 28 05:28 www
$ ls -l /var/www
total 36
drwxr-xr-x  2 root  daemon  512 Mar 28 22:16 acme
drwxr-xr-x  2 root  daemon  512 Mar 14 06:12 bin
drwx-----T  2 www   daemon  512 Oct 12 12:34 cache
drwxr-xr-x  2 root  daemon  512 Mar 14 06:12 cgi-bin
drwxr-xr-x  2 root  daemon  512 Mar 14 06:03 conf
drwxr-xr-x  3 root  daemon  512 Oct 12 12:34 htdocs
drwxr-xr-x  2 root  daemon  512 Mar 29 00:00 logs
drwxr-xr-x  2 root  daemon  512 Oct 12 12:34 run

• Your firewall is not configured to block Let's Encrypt certification verification process. Typically it will initiate a few servers to connect to port 80 on your server.

A successful outcome would result in:

• A ASCII text file, suffixed with .key with your hostname in /etc/ssl/private e.g.

$ doas ls -l /etc/ssl/private
-r--------  1 root  wheel  3272 Mar 28 22:16 example.com.key

• A PEM certificate under /etc/ssl e.g.

$ ls -l /etc/ssl/*.pem
-r--r--r--  1 root  wheel    3937 Mar 28 22:16 example.com.fullchain.pem

It would have the following output of running acme-client, generating a certificate for example.com

acme-client: /etc/ssl/private/example.com.key: generated RSA domain key
acme-client: /etc/acme/letsencrypt-privkey.pem: generated RSA account key
acme-client: https://acme-v02.api.letsencrypt.org/directory: directories
acme-client: acme-v02.api.letsencrypt.org: DNS: 172.65.32.248
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: dochngreq: https://acme-v02.api.letsencrypt.org/acme/authz-v3/3674632835
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: challenge, token: mylkLrPXTvdyiTbDDybKy7M-0JyqiBr0nOg8UXnJ0uDL, uri: https://acme-v02.api.letsencrypt.org/acme/chall-v3/3674632835/-1tUXQ, status: 0
acme-client: /var/www/acme/mylkLrPXTvdyiTbDDybKy7M-0JyqiBr0nOg8UXnJ0uDL: created
acme-client: https://acme-v02.api.letsencrypt.org/acme/chall-v3/3674632835/-1tUXQ: challenge
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: order.status 0
acme-client: dochngreq: https://acme-v02.api.letsencrypt.org/acme/authz-v3/3674632835
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: challenge, token: mylkLrPXTvdyiTbDDybKy7M-0JyqiBr0nOg8UXnJ0uDL, uri: https://acme-v02.api.letsencrypt.org/acme/chall-v3/3674632835/-1tUXQ, status: 2
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: order.status 1
acme-client: https://acme-v02.api.letsencrypt.org/acme/finalize/81817869/2815341474: certificate
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: order.status 3
acme-client: https://acme-v02.api.letsencrypt.org/acme/cert/vxsJMODZOeZxwiuyq9Bz6jqgoRRRUak8ZQ3ob: certificate
acme-client: 172.65.32.248: tls_close: EOF without close notify
acme-client: /etc/ssl/example.com.fullchain.pem: created

Do not request domains you don't own If you change the domains, you need to move the cert and request again