Filezilla 3.50.0 fails where earlier version works (Could not connect to server)

Question

I got a new machine; installed the latest Filezilla (3.50.0). Now I can't make the new version connect to my web site.

Meanwhile, my old machine's Filezilla (3.15.0.2) still connects without a problem.

Both machines are simultaneously going through Wifi to the same Xfinity router, so I can't believe that it is part of the problem.

Things tried:

• Wizard -- I tried a few times with random failures.
• Obvious connections, that I thought should work. Result below
• Copied configuration from old machine. No better. Same result, below.

result:

Status: Resolving address of rjweb.org
Status: Connecting to 67.xxx.xxx.25:21...
Error: Connection timed out after 20 seconds of inactivity
Error: Could not connect to server
Status: Disconnected from server

What has changed? Is there some new setting that is getting in the way? Etc.

More....

traceroute to rjweb.org (67.195.197.25), 64 hops max
  1   10.0.0.1  3.788ms  3.548ms  4.201ms 
  2   96.120.89.105  13.678ms  13.653ms  13.964ms 
...
 12   76.13.1.39  160.754ms  98.743ms  97.254ms 
 13   67.195.197.25  96.906ms  96.977ms  97.913ms 
root@snuc-NUC9i7QNX:/var/log# nc -v 67.195.197.25 21
^C
root@snuc-NUC9i7QNX:/var/log# nc -v 67.195.197.25 80
Connection to 67.195.197.25 80 port [tcp/http] succeeded!
^C
root@snuc-NUC9i7QNX:/var/log# ufw status
Status: inactive
root@snuc-NUC9i7QNX:/var/log# ufw disable
Firewall stopped and disabled on system startup
root@snuc-NUC9i7QNX:/var/log# ufw status
Status: inactive
root@snuc-NUC9i7QNX:/var/log# 

(nc seemed to hang.)