Login Incorrect: Vista XP SP1 and SmartFTP v3.0.1016.7

Background:

SmartFTP v2.5 was logging in successfully to upload.comcast.net with Vista (not XP, sorry about the thread title) before Service Pack 1, but not after.

So I uninstalled 2.5 and installed SmartFTP v3.0.1016.7.

Still can't log in.

I tested the server by installing WS_FTP Home, and using the same account and password it logged in fine.

I prefer the SmartFTP interface (when it works) so I'm hoping for a bugfix or workaround.

Here's the log (no transfer log because the login failed):

[18:58:45] SmartFTP v3.0.1016.7
[18:58:45] Resolving host name "upload.comcast.net"
[18:58:45] Connecting to 216.87.188.9 Port: 21
[18:58:45] Connected to upload.comcast.net.
[18:58:45] 220 FTP server (Version 5.339PWS/AI) ready.
[18:58:45] USER myname@comcast.net
[18:58:45] 331 Password required for myname@comcast.net.
[18:58:45] PASS (hidden)
[18:58:46] 530 Login incorrect.
[18:58:46] Active Help: https://www.smartftp.com/support/kb/51
[18:58:46] QUIT
[18:58:46] 221 Goodbye.
[18:58:46] Connect failed. Waiting to retry (30s)...
[18:58:46] Server closed connection
[18:59:18] Connection attempt 2...
[18:59:18] Resolving host name "upload.comcast.net"
[18:59:18] Connecting to 216.87.188.9 Port: 21
[18:59:18] Connected to upload.comcast.net.
[18:59:18] 220 FTP server (Version 5.339PWS/AI) ready.
[18:59:18] USER myname@comcast.net
[18:59:18] 331 Password required for myname@comcast.net.
[18:59:18] PASS (hidden)
[18:59:19] 530 Login incorrect.
[18:59:19] Active Help: https://www.smartftp.com/support/kb/51
[18:59:19] QUIT
[18:59:19] 221 Goodbye.
[18:59:19] Connect failed. Waiting to retry (30s)...
[18:59:19] Server closed connection