[Samba] Configuration file does not specify default realm

[Dave Close]

I have three Windows 10 boxes which I can successfully access
from Linux using xfreerdp with a command like, "xfreerdp /u:user
/v:machine:3389".  There is no local domain other than whatever the
default might be. There is no domain controller involved. xfreerdp
prompts for domain and password, I just hit enter on the domain
request and, after entering the password, I'm connected.

With winexe I can connect to two of them with a command like,
  "winexe -U .\\user%password //machine systeminfo".
But with the third, I get this response:
  "[ERROR][com.winpr.sspi.Kerberos] -
  [kerberos_AcquireCredentialsHandleA]: krb5_parse_name
  (Configuration file does not specify default realm [-1765328160])".
Some online references tell me to be sure the correct default domain
is in /etc/krb5.conf and, of course, there is no default domain
specified in that file. Clearly it isn't needed for the first two
Windows machines and I don't have a value to put in there anyway.

What could be the cause and/or solution in this case?
-- 
Dave Close, Compata, Irvine CA      "I reserve the right to be smarter
dave at compata.com, +1 714 434 7359    today than I was yesterday."
dhclose at alumni.caltech.edu             -- Konrad Adenauer