I've got a x86 machine running RouterOS 6.36.2, demo license.
I've configured a kvm guest booted with a iso image and no disk image. I can see the guest is up, the CPU is running, when I tried to connect it using vncviewer, the vncviewer show a warning that the connection is not encrypted, and after I click ok, the vncviewer close automatically.

it's that a bug or just not allowed with demo license?

I've checked the debug log of vncviewer, there is nothing but a "CConnection: close: [EndOfStream] The connection closed unexpectedly"

wireshark captured a tcp reset packet from RouterOS.

Does RouterOS x86 run a VNC server? There is no point, since the access is either trough web browser or ssh/telnet - and who would use VNC to see an ssh session?

Does RouterOS x86 run a VNC server? There is no point, since the access is either trough web browser or ssh/telnet - and who would use VNC to see an ssh session?

yes, the RouterOS is running VNC server, I need vnc accessing because the guest system seems do not have console output by default and need graphical installation.

I've purchased a L4 license and still not working, seems I need to contact the support.