It often happens that a domain is moved to another web server or is simply no longer registered and the corresponding certificate needs to be removed from the list of domains that acme.sh maintains. This can be done easily with the following command:
# acme.sh --remove -d my_domain.com
[Wed Feb 1 15:10:58 CEST 2022] my_domain.com is removed, the key and cert files are in /etc/letsencrypt/my_domain.com [Wed Feb 1 15:10:58 CEST 2022] You can remove them by yourself.
# rm -r /etc/letsencrypt/my_domain.com