Vncserver on one Ubuntu box works great; vncserver on a sibling box doesn't.

Here are the VNC processes running on the excellent Ubuntu server:

$ ps -ef | grep vnc
root        1771       1 -     - Dec04 ?        00:00:00 /usr/bin/vncserver-x11-serviced -fg
root        1793    1771 -     - Dec04 ?        00:00:40 /usr/bin/vncserver-x11-core -service
root        2080    1793 -     - Dec04 ?        00:00:14 /usr/bin/vncagent service 0
wyoder      3316    1793 -     - Dec04 ?        00:00:04 /usr/bin/vncserverui service 0
wyoder      3328    3316 -     - Dec04 ?        00:00:00 /usr/bin/vncserverui -statusicon 0
wyoder    233539    3316 -     - 11:06 ?        00:00:00 /usr/bin/vnclicensewiz -pipe 0 -ShowCurrentConfig -teamId s3FOUjVJUyozTuWB7hU -cloudId YRSD4o-YqFKr-X7oBj7 -id 1793_1db472fa559fa58
wyoder    235917  221031 -     - 11:18 pts/10   00:00:00 vncviewer

--and here are the processes on the unsuccessful Ubuntu machine:

$ ps -ef | grep vnc
root        1776       1 -     - 11:01 ?        00:00:00 /usr/bin/vncserver-virtuald -fg
root        1778       1 -     - 11:01 ?        00:00:00 /usr/bin/vncserver-x11-serviced -fg
root        1796    1778 -     - 11:01 ?        00:00:00 /usr/bin/vncserver-x11-core -service
wyoder      4869    3794 -     - 11:17 pts/0    00:00:00 vncviewer

I can connect to machine 1 from machine 2 just fine.  I cannot connect from machine 1 to machine 2.  Instead, machine 1 times out with a "no response" error message.

RVNC Connect shows a green checkmark for machine 1 but not for machine 2.  

Both are running Ubuntu 24.04. What's the diff?  Perhaps a licensing issue?  I believe my licensing should be good for three machines.

Thanks in advance for your help.