Adding ESX Hosts to Distribution Switch

Adding  ESX Hosts to Distribution Switch

I have 2 ESX Hosts that have Standard Switches as shown below:

ESX1 : 192.168.243.101
ESX2: 192.168.243.102

ESX1 has 1 vSS  vswitch0. it has 1 Management vmKernel and 1 VM Network
 ESX 2 has 2 vSS   vswitch0 and vswitch1.  it has 1 Management vmKernel and 3 VM Neteorks

I have created a vDS

Now when I tried to Add Hosts to vDS, I ran into this warning:
I clicked Next  but it did not move to the next screen, it showed up another error :


Any Help in Adding ESX Hosts to vDS ?

Thank you