503 No PORT command issued first

[Jeff Blaine]

Hello, recently my ISP changed their server (I am guessing...since LFTP
used to work and now does not) to ProFTPD 1.2.0.

The mirror command no longer works (which is all I use):

lftp> mirror -R /myarea /
mirror: Access failed: 503 No PORT command issued first.
[ shown for each file that it tries to mirror ]

I have upgraded to LFTP 2.3.11 and the problem persists.

Advice?  Comments?