Was able to login, but not now

Hello,

Recently my server's IP was changed, but everything else remained the same. So I go into SmartFTP and change the host to the new IP, but it fails to login. All the other details haven't changed. But it fails to login now.

I know it's not a firewall or FTP server issue because I can login just fine to this server, with the same name/pwd using XP's command line FTP program. Works fine. But SFTP just gives me:

[19:28:29] SmartFTP v2.0.996.12
[19:28:30] sfFTPLib is not licensed.
[19:28:30] Cannot login waiting to retry (30s)...

Any ideas what's going on?

Thank you mb, that worked. But why did it work?