Some of us want use LetsEncrypt with Foreman 3.0.1 ( in my case )
letsencrypt was installed on my Ubuntu 20.02 LTS Server.
Now I installed Foreman 3.0.1 and I want that Foreman use letsencrypt.
# foreman-installer \ --foreman-server-ssl-cert /etc/letsencrypt/live/foreman.local/cert.pem \ --foreman-server-ssl-chain /etc/letsencrypt/live/foreman.local/chain.pem \ --foreman-server-ssl-key /etc/letsencrypt/live/foreman.local/privkey.pem \ --foreman-proxy-foreman-ssl-ca /etc/ssl/certs/ca-certificates.crt \ --puppet-server-foreman-ssl-ca /etc/ssl/certs/ca-certificates.crt
*foreman.local = should be different on your Server.
Now Foreman use letsencrypt.
I hope I could help you