For anyone else wondering, this is how I got it to work. The following is my /etc/apache2/sites-available/000-default.conf doing a reverse proxy.


        ServerName domain.tld
        ProxyPass / http://xxx.xxx.xxx.xxx:xx/
        ProxyPassReverse / http://xxx.xxx.xxx.xxx:xx/
        RedirectMatch ^/$ https://domain.tld/
        SSLEngine on
        SSLCertificateFile /etc/ssl/path-to/domain.crt
        SSLCertificateKeyFile /etc/ssl/path-to/domain.key
   LogLevel info ssl:warn
   ErrorLog ${APACHE_LOG_DIR}/error.log
   CustomLog ${APACHE_LOG_DIR}/access.log combined