When creating a virtual switch, the number of virtual switch ports must be specified. If there are no more free virtual switch ports on the destination node, the new VMs are silently disconnected.
To re-connect these VMs, access the settings and select an alternate virtual switch or migrate back to the original node. Once here, the network connection can be re-set.
The number of virtual switchports on a virtual switch can be adjusted, but this requires a reboot of the ESX node.
