Create a subdomain and rename your droplet to that FQDN (fully qualified domain name) -- e.g. d.omain.com
cat /etc/letsencrypt/live/d.omain.com/{privkey,fullchain}.pem > znc.pem
cd /etc/letsencrypt/renewal-hooks/deploy touch update-znc.pem chmod +x update-znc.pem nano update-znc.pem
12 3 * * * cat /etc/letsencrypt/live/d.omain.com/{privkey,fullchain}.pem > /home/znc-admin/.znc/znc.pem
/server add $1 d.omain.com/9001 -ssl -username=yourusername/$1 -password=***** -autoconnect; /wait 1 /connect $1