After changing hostname of your VPS, you need to restart VPS (Type sudo reboot in command line). This will solve the issue, “Unable to resolve hostname”.
Linode 1 GB is a good start to host single or multiple websites. It costs 10 USD per month. We recommend you buy VPS hosting from Linode only because it is awesome.
If you have ever thought of creating a website for your own or your company, the very first thing you should buy is a name for it, which is called “domain name”.