OK, I disabled the varnish with this command:
"sudo mv /opt/bitnami/varnish/scripts/ctl.sh /opt/bitnami/varnish/scripts/ctl.sh.disabled" and
restarted the services. After I redirected again the HTTP to HTTPS in "/opt/bitnami/apache2/conf/bitnami/bitnami.conf" file. The http traffic is forced to https, and it works fine. Thank you.
I need some further explanation: why does Bitnami include Varnish in the Magneto AWS stack if the Varnish basically incompatible forcing https? I guess almost 100% of magento sites force redirection to https so I just don't understand the logic.
Other question: now I can access only on https. On the welcoming page there is a message "Awesome! Magento is now installed. Access Magento" But there is no page on the "domain.com/manegnto/" link. How can I log in as admin?