Then there's something on the PC that is preventing the service from reaching our network.
If the install was done as Administrator, then it should have worked but if it didn't, then something else on the PC overrode the installer trying to give itself the required firewall access.
You can manually add those. Check out this post.
https://support.outagesio.com/topic/9/howto-no-hops-no-pings-in-your-dashboard