How to use Nautilus as FTP: Connect to Server not working

Just below the textbox is the example of what to enter. So your entry should look like these:

ftp://mydomain.com 

Or

ftp://www.mydomain.com

Also check to see if your ftp server allows connections from your machine as I'm assuming you might have used ftp on another system and it worked quite well. Also do all other normal checks to see if you can ping your server you are trying to reach to make sure your machine isn't having problems altogether just to do some elimination.

EDIT:

If you are trying to connect a server on your local network then the same above applies with the hostname of the system or if none is set the IP address should work as well. Example:

ftp://127.0.0.1

Or

ftp://myothermachine