Problème Xibo server

Hello, I have a small problem. I succeeded the installation of xibo server on ubuntu 16.04 32bits, but during the check with the address ip in the url of a browser here is what I obtain! Someone can help me by giving me a runway or anything? Thank you in advance.

Most likely the DocumentRoot and url rewriting is incorrect, please see http://xibo.org.uk/manual/en/install_environment.html

Thanks for your fast answer! I have make a symlink for the cms files like this “sudo chown -R www-data.www-data /xibo-library” but it doesn’t work.