Installatron error:

FAILURE [3; /opt/curlssl/bin/curl] https://server.com/install/index.php?installFixtures=true&_1518181922185 [http code=0; timeout=10]

You should fine all htaccess and disable them, if they have some server side directives like AddHandler and etc.

If that didn’t work then we’ll try a debug log;

. First, just before you press the [Install] button run these commands:
rm -f /var/installatron/logs/*
echo “debug=yes” >> /usr/local/installatron/etc/settings.ini
. Now press the [Install] button.
. Then when the install process fails immediately remove “debug=yes” from the end of: /usr/local/installatron/etc/settings.ini

That will build a detailed ‘debug_log’. They aren’t always easy to read