vMotion's failing for VM's connected to NSX segments with error "The object or item referred to could not be found. vDS dvs port XXX cannot be found"

Products

• VMware NSX
• VMware vCenter Server

Issue/Introduction

• You see the following error in vSphere UI when attempting to vMotion/migrate or power on a VM. 

•  You also see vCenter Server vpxd log prints similar to below when this error occurs.

2021-07-##T04:02:50.903Z info vpxd[38566] [Originator@6876 sub=Default opID=St-1626148968#######-74-01-01-02-01] [VpxLRO] -- ERROR lro-1548339 --  -- VmprovWorkflow: vim.fault.NotFound:
--> Result:
--> (vim.fault.NotFound) {
-->    faultCause = (vmodl.MethodFault) null, 
-->    faultMessage = (vmodl.LocalizableMessage) [
-->       (vmodl.LocalizableMessage) {
-->          key = "com.vmware.vim.vpxd.dvs.portNotFound.label", 
-->          arg = (vmodl.KeyAnyValue) [
-->             (vmodl.KeyAnyValue) {
-->                key = "port", 
-->                value = ""
-->             }
-->          ], 
-->          message = <unset>
-->       }
-->    ]
-->    msg = ""
--> }
--> Args:
--> 

Environment

vCenter Server 7.0 U3p or lower

VMware NSX

Cause

Prior to vCenter Server version 7.0 U3q, when a VM template is migrated from one host to another, the proxy switch of the host with the dvport used by the VM is not updated by host-sync due to the nature of VM templates. The logical switch port validation when a normal VM migrates may fail due to the empty port references. In vCenter Server 7.0 U3q and later, the proxy switch is not validated for normal VM vMotion migrations. 

Resolution

This is fixed in vCenter Server version 7.0 U3q. 

Workaround:

1. Select the VM which is not powering on or failing to vMotion.
2. Select 'Edit Settings' on VM and change the network to a different network like 'VM Network'.
3. Try to power the VM on or vMotion it. This should be successful. 
4. Power off the VM.
5. Change the network back to the originally assigned network. 
6. Power VM back on.