Error 500

Without making changes (and even after a reoot) I get a log like this:

[14:23:29] Server closed connection
[14:23:29] Cannot login waiting to retry (30s)...
[14:23:59] Continue to login attempt 5...
[14:23:59] Resolving host name "ftp.conservative-judaism.org"
[14:23:59] Connecting to 66.96.81.106 Port: 21
[14:23:59] Connected to ftp.conservative-judaism.org.
[14:23:59] 220 ProFTPD 1.3.0rc5 Server (Main FTP Server) [66.96.81.106]
[14:23:59] 500 not understood
[14:23:59] Server closed connection
[14:23:59] Cannot login waiting to retry (30s)...
[14:24:29] Continue to login attempt 6...
[14:24:29] Resolving host name "ftp.conservative-judaism.org"
[14:24:29] Connecting to 66.96.81.106 Port: 21
[14:24:29] Connected to ftp.conservative-judaism.org.
[14:24:29] 220 ProFTPD 1.3.0rc5 Server (Main FTP Server) [66.96.81.106]
[14:24:29] 500 not understood
[14:24:29] Server closed connection
[14:24:29] Cannot login waiting to retry (30s)...
[14:24:59] Continue to login attempt 7...
[14:24:59] Resolving host name "ftp.conservative-judaism.org"
[14:24:59] Connecting to 66.96.81.106 Port: 21
[14:24:59] Connected to ftp.conservative-judaism.org.
[14:24:59] 220 ProFTPD 1.3.0rc5 Server (Main FTP Server) [66.96.81.106]
[14:24:59] 500 not understood
[14:24:59] Server closed connection
[14:24:59] Cannot login waiting to retry (30s)..

I have not made any changes to my connection, PC or ftp server.
This has happened before but I don't know why or how it resolved.

Any ideas?
I have feat off

Is there any way to log raw commands sent to and from the server?
Maybe that can help me track this down:

TIA