[www-email-discuss] <none>

I can´t reach to http://www.artchive.com 
I send an email to www4mail@wm.ictp.trieste.it with the body : Tsource http://www.artchive.com 
but I receive bad news, because my email server told me: "Please confirm the HOSTNAME, the machine does not exist."
How can I know if that machine exist really? 
I knew and was adviced to visit that site for my subscribe from TOURBUS@listserv.aol.com 
That www site could be very important for me.
I hope hears from yours.