Tried to uninstall/reinstall the template, always got the same screen. Tried 3 different PCs with different OS and browser (Firefox both for Win10 and Mac, Safari, Chrome and Edge). I checked with my hosting support and they confirmed me on their side everything's fine. I'm not a programmer, just a content editor with basic Joomla skills.

My sistem info, if they're useful:
PHP attivo su Linux serv01.ams23.siteground.eu 3.12.18-clouder0 #2 SMP Fri Oct 23 11:20:57 EEST 2015 x86_64
Versione database 5.5.44-37.3-log
Collation database utf8_general_ci
Versione PHP 5.3.29
Web Server Apache
WebServer interfaccia PHP cgi-fcgi
Versione di Joomla! Joomla! 3.4.8 Stable [ Ember ] 24-December-2015 19:30 GMT
Versione piattaforma Joomla! Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent Mozilla/5.0 (Windows NT 10.0; WOW64; rv:44.0) Gecko/20100101 Firefox/44.0
I hope you can help me.
Thank you!