Thank you for your reply.
I tried to stop apache service.But it could not to be done.
$ sudo /usr/sbin/apachectl stop
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message
httpd (no pid file) not running
Alternatively, I tried below and it seems to be stopped.
$ sudo /opt/bitnami/ctlscript.sh status
php-fpm not running
apache not running
mysql not running
As you say, my vm instance's ports are note externally available. I didn't know the reason why it is happened.
But then I could renew the certificate the article (@davidg shared)
Thank you all for your advice!!