SUMMARY: I cannot find any mechanism to connect from Windows to a CentOS 7 Gnome desktop running vino-server.

I can connect with 'vinagre' from a CentOS 6 desktop but that's not useful to me.

DETAILS:
My primary desktop is a Windows 10 Pro system with a "4K" (3840 x 2160) 39 inch monitor.

I run multiple other systems (Windows, Mac, Linux) both as hardware and as virtual machines. It is must useful to me to connect to the desktops of those systems from this central point.

I use RealVNC 5.3 Enterprise for most of those connections.

I am now making the (painful) transition to CentOS 7 after CentOS 5 hit end-of-life on March 31, 2017.

We still build on CentOS 5 so we can run on 6 and 7 and I have no problems using CentOS 5 or 6.

I also run Ubuntu 16 with some network emulation software.

I can connect from Windows 10 using RealVNC Viewer 5.5.1 Enterprise to the desktops of the CentOS 6 and Ubuntu systems (both running vino-server) without any problems.

Somehow the vino-server on CentOS 7 is not working. I consistently get "Unable to connect to VNC Server using your chosne security setting. Either upgrade VNC Server to a more recent version or select a weaker level of encryption"

Even if I set the VNC Viewer to Prefer Off, I still get this message.

Note that I can connect to the CentOS 7 desktop if I run 'vinagre' on a CentOS 6 desktop but that's not useful!

I won't be much help because I'm not on a server.

Has upgrading your VNC Server helped at all?

The current version is 6.0.2.
https://www.realvnc.com/download/vnc/

I'm not sure if selecting a weaker level of encryption is the best practice.
Best to wait on members that know.

Maybe vino encryption has to been turned off? (guessing)

http://askubuntu.com/questions/73285...om-a-window-pc

Sorry I don't know more....hope you get it fixed.

The issue was connecting to the built-in Gnome vino-server.

This used to work from any VNC viewer. In CentOS 7 it does not work except with 'vinagre' which does not run on Windows.

I gave up on making this work and installed RealVNC Enterprise 5.3 (which I have licensed)!

Note that RealVNC does not work with a Gnome desktop but once I switched to KDE I can share the desktop with RealVNC and connect to it with RealVNC Viewer.

I had to add KDE using:

sudo yum install @kde-desktop

I think I could have done this with the tightvnc-vnc-server but I don't really care at this point.

I have not yet tried the new VNC Connect (which is what version 6.0.2 is called).
It uses a server rendezvous technique much like TeamViewer to allow connections behind NAT without port forwarding.

As for TeamViewer, I also have a TeamViewer 12 Professional license but I find VNC connections work much faster in the LAN.

Did installing KDE fix the issue?

I thought about TigerVNC but wasn't sure if it would work.

"The issue" was trying to connect to Gnome's built-in vino-server from a Windows client.

The KDE desktop does not have the built-in vino-server, so KDE "fixed" the issue only in that it allowed RealVNC to work to share the console!

I suspect that I could have used the TigerVNC server instead of RealVNC.

I'm not sure if TigerVNC would be much more different than RealVNC.

Sorry I can help with Windows. I haven't used Windows in about 7 years.
It sounds like (I could be wrong) that something on your Windows Client just isn't playing nice with Gnome's built-in vino-server.

Looking in my Red Hat Study Guide Book I found out that:
Samba enables Windows Clients access to Linux fs and printers.
Make sure you have samba installed.

-::-Maybe others will see your thread and know how you can get things working from your Windows Client.-::-