I have a DSL connection which means when you restart your computer you receive a new IP address.
Go to www.whatismyip.com and check your ip address. I had thought it was 192.168.1...same as the router, it's not.
Using that IP to log on solved my problem of getting that error message.
im making a small ftp server using serv-u. i have an ip and a domain and i set up serv-u with it. when i try to log in from a different computer, i get a 401 Authorization Required screen. I checked the settings over and over. now when i try to log in, the sign in window just keeps popping up. any ideas?