Letsencrypt add domain to existing certificate

I am just simply trying to add the domain test.example.com to the certificate that already exists for example.com. How do I add a domain to my existing certificate and replace the old certificate?

I have tried these few commands

./letsencrypt-auto certonly --cert-path /etc/letsencrypt/archive/example.com --expand -d test.example.com

./letsencrypt-auto certonly -d example.com --expand -d test.example.com

Result: both created a brand new cert in a new folder test.example.com-0001

./letsencrypt-auto certonly --renew-by-default  --expand -d test.example.com

Result: error folder test.example.com already exists.

./letsencrypt-auto renew --expand -d orange.fidka.com

Result: error, I can only renew if my certificate is expired.

You need to specify all of the names, including those already registered.

I used the following command originally to register some certificates:

/opt/certbot/certbot-auto certonly --webroot --agree-tos -w /srv/www/letsencrypt/ \
--email me@example.com \
--expand -d example.com,www.example.com

... and just now I successfully used the following command to expand my registration to include a new subdomain as a SAN:

/opt/certbot/certbot-auto certonly --webroot --agree-tos -w /srv/www/letsencrypt/ \
--expand -d example.com,www.example.com,click.example.com

From the documentation:

>--expand "If an existing cert covers some subset of the requested names, always expand and replace it with the additional names."

Don't forget to restart the server to load the new certificates if you are running nginx.

Apache on Ubuntu, using the Apache plugin:

sudo certbot certonly --cert-name example.com -d m.example.com,www.m.example.com

The above command is vividly explained in the Certbot user guide on changing a certificate's domain names. Note that the command for changing a certificate's domain names applies to adding new domain names as well.

Edit

If running the above command gives you the error message

> Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA.

follow these instructions from the Let's Encrypt Community

This is how i registered my domain:

sudo letsencrypt --apache -d mydomain.com

Then it was possible to use the same command with additional domains and follow the instructions:

sudo letsencrypt --apache -d mydomain.com,x.mydomain.com,y.mydomain.com

You can replace the certificate by just running the certbot again with ./certbot-auto certonly

You will be prompted with this message if you try to generate a certificate for a domain that you have already covered by an existing certificate:

-------------------------------------------------------------------------------
You have an existing certificate that contains a portion of the domains you
requested (ref: /etc/letsencrypt/renewal/<domain>.conf)

It contains these names: <domain>

You requested these names for the new certificate: <domain>,
<the domain you want to add to the cert>.

Do you want to expand and replace this existing certificate with the new
certificate?
-------------------------------------------------------------------------------

Just chose Expand and replace it.

I was able to setup a SSL certificated for a domain AND multiple subdomains by using using --cert-name combined with --expand options.

See official certbot-auto documentation at https://certbot.eff.org/docs/using.html

Example:

certbot-auto certonly --cert-name mydomain.com.br \
--renew-by-default -a webroot -n --expand \
--webroot-path=/usr/share/nginx/html \
-d mydomain.com.br \
-d www.mydomain.com.br \
-d aaa1.com.br \
-d aaa2.com.br \
-d aaa3.com.br

this worked for me

 sudo letsencrypt certonly -a webroot --webroot-path=/var/www/html -d
 domain.com -d www.domain.com