Asus Merlin 384.19
acme.sh v2.8.3
(domain.name).key and fullchain.cer were present in the /jffs/.le/(domain.name)/ folder
Used openssl x509 -in certificate.pem -text -noout to view the contents and check DATE & domain.name
Used scp to copy both files to local pc and "Import your own certificate" into router
PLEX
First, create/renew certificate on owncloud server.
move /etc/letsencypt/live/"server-name"/cert.pem chain.pem privkey.pem
to ~/le-pkcs, then
run below to create the .pfx file.
openssl pkcs12 -export -out server-name.com.pfx -in cert.pem -inkey privkey.pem -certfile chain.pem -name "server-name"
move server-name.pfx to plex-server-name:~/scripts/PlexCustomSSL/
restart plexmediaserver