Renew Ghost Let's Encrypt SSL

SSH to your instance and switch to ghost's user.
Then following these commands:

1. Install latest ghost-cli
sudo npm i -g ghost-cli@latest

2. Renew certificate
ghost setup ssl-renew

3. Switch to root user
sudo su

4. Upgrade acme.sh inside letsencrypt
"/etc/letsencrypt"/acme.sh --upgrade --home "/etc/letsencrypt"

5. Renew SSL through acme.sh
"/etc/letsencrypt"/acme.sh --cron --home "/etc/letsencrypt" --debug --log

Reload browser, Tada!