DNS No Valid NameServers Responded

[MarioLaul]

Hi.
After last update (0.9.8 release 23) my domain nsc.ee not working anymore. VPS Server show me after login "sudo: unable to resolve host mail.nsc.ee". Only child domains working http://pilv.nsc.ee. And mail not working too.

If i write "hostname" in terminal - showing "mail.nsc.ee"
if i ping nsc.ee in terminal - showing "ping: unknown host nsc.ee" -> same ns1.nsc.ee and ns2.nsc.ee
if i look "/etc/hostname " in terminal - showing "mail.nsc.ee"
if i look "/etc/hosts" in terminal - showing

127.0.0.1 localhost
127.0.1.1 mario

::1 localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

how can i fix all?

my mails and domain not working, but i really need access my mail account and my websites. Help me..