All my network is down, is this a DNS problem?

I'm using domain mapping plugin in one network and since yesterday everything is broken.
I think this is a DNS problem but since i did not touched/updated anything in this website since a week ago and everything was working as expected 'till yesterday afternoon I would like to know what's happening. The main network website is: webserviceprovideo.com

all the mapped domains are broken though...

http://www.mavidriver.it
http://graficheprovideo.it
http://www.itervitis-magon.eu
http://dmi-it.com/
http://improntaitalia.it

Why is this happening?!