In Hamachi, you can right-click the other peers and use Diagnose.
You need to have all four checks ending with OK. I have attached an example when my PC is configured properly, but their PC is not, so it fails saying their inbound traffic is blocked. Commonly this is caused by the firewall.
Another issue is when Hamachi doesn't install the VPN network correctly. I had to reinstall Hamachi before it would see another PC on the virtual network.
Screenshot attached of what network adapter should be showing.