When verifying the selection of lab host group for a team project collection (screen shot below), I was getting a warning: Permission verification failed for: [host group:All Hosts\XXX, host:XXX.XXX.XXXl] TF259194: Team Foundation Server could not reach host XXX.XXX.XXX. Ensure that the host is available and try again..
We followed one of the recommendation in this Microsoft connect issue, which was to ping the VM host server from the TFS server.
We could not ping the server but we could access a network share that on that server. That lead to thinking it could be firewall issue
Our solution was to activate in the firewall activate the ICMP file sharing echo request (see screen shot below)
After verified the host groups again, the warning disappeared
