Moving CI website to another server - only blank page showing

How did you place the files and folders of CodeIgniter relative to the website root (public) folder?

The website root folder is the /var/www/html/, and I put the webpage to the /var/www/html/szig/ folder.

Please describe the contents (files and folders) in /var/www/html/szig/

Is index.php in /var/www/html/szig/?

Have you set up a virtual host that sets the DocumentRoot to /var/www/html/szig/?

If you have set up a virtual host what is the ServerName you gave it?

The directory structure:
https://pastebin.com/hJeA8yk5

The directory structure with files:
(this is a big file...) http://tbc_z87.fw.hu/temp/ktfa2.txt


The index.php is in the /var/www/html/szig/public_html folder.
I don't  set virtual host in the apache config.