rm -f /etc/letsencrypt/live/mydomain.net/privkey.pem && rm -f /etc/letsencrypt/live/mydomain.net/fullchain.pem
rm -f /etc/letsencrypt/live/mail.mydomain.net/privkey.pem && rm -f /etc/letsencrypt/live/mail.mydomain.net/fullchain.pem
rm -f /etc/letsencrypt/live/ssl.mydomain.net/privkey.pem && rm -f /etc/letsencrypt/live/ssl.mydomain.net/fullchain.pem
Run them line by line replace mydomain.net with your own domain