An administrator is commissioning a Nutanix Enterprise Cloud.

According to the web search results, one possible cause of inter-VM communication failure between hosts is that the switch is not configured to allow VLAN 15 traffic. VLAN 15 is the default VLAN ID used by AHV for internal communication between CVMs and hosts. If the switch blocks or drops VLAN 15 packets, it will prevent inter-VM communication across hosts4. To enable full inter-VM communication, the administrator should update the switch to specifically allow VLAN 15 traffic on the ports connected to the AHV hosts.