Wow, I didn't know that before. And it seems that you are the only one who's helping me.
I thank you for this.
Okay what about issue ssl certificates on every subdomains? Such run this command
/opt/letsencrypt/letsencrypt-auto certonly --webroot -w /var/www/idevangelist.com/htdocs/ -d idevangelist.com . -d unity.idevangelist.com -d gamedev.idevangelist.com -d android.idevangelist.com --email myemail@gmail.com --text --agree-tos ?