It seems like my SSL won't auto-renew itself whether from Cron Task or manually. It has been like this for more than 6 months. In the past I have to let it expire and re-apply for new one.
Please note that I use 'File verification' method for SSL and I have Nginx free firewall 1.0 and Fail2ban 1.7 enabled.
Below it the error message I found in Cron's log.