Today I installed Videostream Google Chrome extension on my PC, but while playing videos I was getting “We couldn’t make a connection to your Chromecast” error message.
As per above error message I Disabled my PC firewall and enabled Incoming TCP port 5556
but no luck.
Then finally I closed/Stopped my Antivirus i.e. Microsoft Forefront Client security and I was finally able to cast videos from my PC to ChromeCast via Videostream.