[CentOS] off-topic question about RDP to Win-10

I have a win10 VM in virtualbox on my Linux (C7) desktop. I CAN connect
to it with rdesktop 1.8.3 (now rather old, but it's the latest release),
but cannot connect with remmina or krdc. Both of them just hang for a
while then say they can't connect.

Curiously, they all will connect to the win10 box in my office.

They don't show any other useful information, and I don't know where
to go to figure this out. Anyone out there have any ideas they can share?

thanks in advance!

Fred
-- 
-------------------------------------------------------------------------------
 .----    Fred Smith   /              
( /__  ,__.   __   __ /  __   : /     
 /    /  /   /__) /  /  /__) .+'           Home: fredex at fcshome.stoneham.ma.us 
/    /  (__ (___ (__(_ (___ / :__                                 781-438-5471 
-------------------------------- Jude 1:24,25 ---------------------------------