Guest VMs cant reach each other on Different ESXi Servers

I have two vSphere EXSI 6 servers both setup with the same vSwitchs and connected to the same physical switches

Server 1:

• eth0 => vlan143 (mapped to CORE/Management vSwitch)
• eht1 => vlan140 (mapped to SAT vSwitch)
• eth2 => vlan141 (mapped to ACK vSwitch)

Server 2:

• eth0 => vlan143 (mapped to CORE/Management vSwitch)
• eht1 => vlan140 (mapped to SAT vSwitch)
• eth2 => vlan141 (mapped to ACK vSwitch)

The problem I have is that the Guest VMs on Server 1 cant reach the Guest VMs on Server 2 which are all on the same vSwitches. Both sets of Guests can reach servers that are on vlan143.

The NICs on each host connect to a single physical switch, this switch has the ports setup as access ports.

The two guest are running Windows Server 2008

There is not any VLAN Tagging enabled on the vSwitchs or host interfaces, as when I do connectivity completely breaks down. The Physical switchs do have Vlans.

Appreciate any help or advice offered.

UPDATE 19 April 2016...

OK I think I have found the cause to this, I have noticed that some of the VM's on either ESXI server are not displaying their MAC address's when looking at the vSwitch overview see Screen Grabs Below.

VMServer 1 vSwitch VMServer 2 vSwitch

Now I can reach the VMs from each server that are displaying the MAC addresses, but those that are not showing MACs cant reach the VMs on the other servers. Any help greatly appreciated.