The config file is as below. It's the one I got from the sandbox details sent by email. I just overwrote the default one created by the generator. I also copied the RSA files into the RSA folder, to match the config file.

host: develop2.symphony.com
bot:
    username: devcertbot1895
    privateKey:
        path: rsa/devcertbot1895-private.pem

I have confirmed I have no proxy configured anywhere on my home network (I would have been surprised if there was). I have checked using Internet Explorer> Internet options>Connections>LAN Settings. I have also checked with commandline netsh winhttp show proxy, and it clearly says " Direct access (no proxy server)." Yet I'm still unable to connect. The thing is, when I try to connect with default port 443, the system bombs out completely with the below error on trying to start the datafeed:...

Thanks Yong for your quick response! Let me follow your instructions, and I will update on here how things go.