A firewall is blocking inbound traffic on TCP port 80, which is used to serve content to requesting computers. As a result, ...

A firewall is blocking inbound traffic on TCP port 80, which is used to serve content to requesting computers. As a result, other computers on the network, including the Hosted Cache server, cannot retrieve content from this client. 
To create a Windows Firewall rule that allows inbound traffic on TCP port 80, run the enable cmdlet appropriate to your service mode from an elevated PowerShell command prompt. If a different firewall is used, modify the firewall settings to allow this traffic.