Error While Installing ERPNext on Ubutu

Hi Everyone,
While installing ERPNext on an Ubuntu Machine.

sudo bash --setup-production
Installing for Ubuntu vivid amd64
In case you encounter an error, you can post on

Adding ubuntu mariadb repo
Installing packages for Ubuntu. This might take time…
Installing wkhtmltopdf
Installing wkhtmltox package for trusty (Ubuntu 14.4) even if you are using vivid.
–2016-02-24 11:49:51--
Resolving (… failed: No address associated with hostname.
wget: unable to resolve host address ‘

Any idea about it?

I just tested the site, and it is up and running. Sounds like an issue with your DNS server

how do u fix DNS Server issues?