If you are trying to connect by name instead of by IP address then that will only work if the name exists in your hosts file, or in your name resolution system; such as if you registered the name in an "A" record with the Internic or other authorized domain registrar. As your raspberry is almost certainly operating on a private IP address rather than a public IP address, no domain registrar would allow you to register it.
You could create a local DHCP server with a fixed hostname for the Raspberry.
Or you could switch to using IP address instead of name to talk to it.
