Start by getting the serial number in your SOA record fixed.
Currently it is:
artproject.it. 5940 IN SOA dns.technorail.com. hostmaster.artproject.it. 1 86400 7200 2592000 3600
the '1' is just wrong. it should be something like
kitsune.dk. 3600 IN SOA ns1.quickdns.dk. hostmaster.quickdns.dk. 2016040904 14400 7200 2415600 3600
The '2016040904' is the serial number of the zone, and yes it is supposed to be formatted like a date with an additional 2-digit count. It must be increased every time the zone is modified, so don't set it to an arbitrarily huge value - that will cause really-hard-to-fix problems.
[root@cm3 blocktester]# ping artproject.it
ping: artproject.it: No address associated with hostname