This problem is caused when your computer cannot turn the domain name into an address that it can understand. There are several reasons for this.
If you are trying to ftp or publish, the problem may be getting the case sensitive username and password slightly wrong or copying in picking up a space.
It may also be due to the 24-48 hours it takes for a new domain name to be propagated on the Internet DNS. Until this is done and your and other ISPs have updated their DNS tables, you will not be able to find the site as they will not know where to direct your request
The most common cause is that the wrong FTP host address/name is being used. In order to keep things simple we have made this just your domain name. So for example if your domain name is www.youredomain.com then this is the host address that you must use to FTP to. If you use ftp.yourdomain.com instead of www.yourdomain.com then you will get this error message.
If you are using the correct host address and you still get this error message then the problem could be that your ISP is not getting the correct machine address when you ask it to. The way to check this is to go to the dos prompt and type:
If this returns an 'Unknown Host' error then you will need to contact you ISP or system administrator. If it does not return an error but pings the website then you will need to contact the support department including the entire error message and all the settings that you are using.