I would test the connection from the client machine to the server by opening a terminal in the client and executing the command: telnet <server> <port>
where <server> is the server where the Virtual DataPort server is running and <port> is the server port, 9999 by default. You can find the default ports in the [User Manual](https://community.denodo.com/docs/html/browse/8.0/en/platform/installation/appendix/default_ports_used_by_the_denodo_platform_modules/default_ports_used_by_the_denodo_platform_modules).
If that doesn't solve the issue, I would check the admin tool's logs which can be found in the client at <DenodoHome>\logs\vdp-admin. This could give you more information about why the connection is timing out.
Hope this helps!