The set up looks ok - Are the two VMs configured to get their IP addresses via DHCP? Can you post the NIC configuration from the VM's OS? If one VM is able to get an IP address and the other one does not than there might an issue with your DHCP server only having a limited of IP addresses to assign
You may also want to check the physical switch, to ensure it allows multiple MAC addresses on the port. Some manage switches come with port security enabled which does cause issues like this.
André
