Trying to access our FTP server. Getting "Killed 9." How do I resolve this?

I just tried to access our FTP server via the command-line FTP client on my new M2 Mini. And it gives an immediate "Killed 9" message. On my 2017 iMac (Catalina): (Note that the ftp server domain name "has been changed to protect the innocent")

ftp xxx.com
Connected to xxx.com.
220 (vsFTPd 3.0.2)
Name (xxx.com:foo): yyy
331 Please specify the password.
Password: 
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp>

On an AS/400 in the cloud:

Connecting to host XXX.COM at address 35.174.190.169 using port 21.
  220 (vsFTPd 3.0.2)                                                      
> yyy                                                                
  331 Please specify the password.                                        
  230 Login successful.                                                   
  UNIX Type: L8

On my M2 Mini:

ftp xxx.com
Killed: 9

On my M2 Mini, trying to connect to an FTP server on the same LAN, only one desk over, server name in my host table, that also works just fine from my 2017 iMac, and from a couple of AS/400s in the same room:

ftp europa
Killed: 9

The ftp *and telnet* commands *both* fail with Killed 9 on the Mini, *even if I don't specify a server.* And that doesn't happen on the 2017 iMac. I'm pretty sure I had to stick both the command line FTP and the command line Telnet back onto the iMac when I updated it to Catalina.