How to troubleshoot no connect issues?

[hellovnc]

Hello,
Running server version 1.4.2.0
Windows 10 2H22
Other computers at this location do work.
I am using ZeroTier private networking since I do not have ability to adjust corporate firewall.

I have access to the remote machine via the evil TeamViewer, for testing.

I can connect to UNV server at the machine, using loclhost (127.0.0.1) on port 5900, that works.
But I cannot connect from outside the network.
I turned off windows firewall. No difference.

From the viewer, I do not get a login prompt, just a timeout.

From my local computer running the viewer, I use Windows Telnet to the Zerotier IP on port 5900, and I get a connection, and the text
RFB 003.008
(that makes me think the port is open and receiving the request...)

I enabled logging.
Here is some stuff from the log, but I do not understand it.

Wed May 3 17:28:04 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : WinVNCAPPMain-----Application started
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : server created ok
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : OpenInputdesktop OK
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : SelectHDESK to Default (228) from bc
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : Username SYSTEM
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : vncmenu(server)
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : clearing user settings
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : SockConnect 1
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : trying port number 5900
Wed May 3 17:28:06 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vsocket.cpp : closing socket
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : SockConnect Done 1
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncsockconnect.cpp : started socket connection thread
Wed May 3 17:28:34 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : show user properties requested
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : INITDIALOG properties
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : clearing user settings
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : SockConnect 1
Wed May 3 17:29:10 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : SockConnect 1
Wed May 3 17:29:11 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : saving current settings to registry
Wed May 3 17:29:27 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : SockConnect 1
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : saving current settings to registry
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : enddialog (OK)
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncproperties.cpp : dialog result = 1
Wed May 3 17:33:57 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : vncMenu::Shutdown: Close menu - Disconnect all - Shutdown server
--The system cannot find the file specified.
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : vncMenu WM_CLOSE call - All cleanup done
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : quitting from WM_DESTROY
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : KillAuthClients() done
--Invalid window handle.
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncmenu.cpp : vncmenu killed
--Invalid window handle.
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : ################## Closing Imp Thread
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\winvnc.cpp : ################## SHUTING DOWN SERVER ####################
--Attempt to release mutex not owned by caller.
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : shutting down server object1
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vsocket.cpp : shutdown socket
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vsocket.cpp : closing socket
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncsockconnect.cpp : quitting socket connection thread
--A blocking operation was interrupted by a call to WSACancelBlockingCall.
Wed May 3 17:33:59 2023
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vsocket.cpp : closing socket
--No connection could be made because the target machine actively refused it.
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : KillAuthClients() done
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : KillUnauthClients() done
C:\Users\rudi\Desktop\git_ultravnc\winvnc\winvnc\vncserver.cpp : ~server m_pDSMPlugin = NULL

What suggestions do you have to troubleshoot this?

Are there entries in Windows Event Viewer which I could search for, to determine if there is some other secret / stupid security policy or program which is preventing the connection via VNC? since telnet works, I am stumped. i.e. are there keywords I can search the event viewer, ie using port 5900 ?

Thank you.

[Rudi De Vos]

Other computers at this location do work.

Make a copy of the ultravnc.ini of a working computer, and use this on the bad one. ( rename the old ini to see if anything is different)
ini files are portable, you can create it on any pc you want.

Does it work on the LAN, connect from other pc on the same network to this PC.

show user properties requested (log): Was you opening th user settings ? In case no password is set, the properties are also openened
Is winvnc started as application ?

[hellovnc]

thanks for reply.
winvnc is running as a service.

log, show usr props: yes i probably did try to open settings during trblshooting. it logd that.

does not work on local lan. I truely think this is some sort of security issue on this pc, but firewall is off.
I'm just not sure where else to look.

I will make copy of ini and try it again.
thank you