openssl s_client -connect <server.tld>:443 | tee <server.tld>_out_cert

openssl x509 -inform PEM -in <server.tld>_out_cert -text -out <server.tld>_out_cert.pem

mv <server.tld>_out_cert.pem /etc/ssl/certs

cd /etc/ssl/certs

c_rehash

vi rtorrent.rc, add config below, and restart rtorrent.

# Self_signed Certs network.http.capath = /etc/ssl/certs/