VM reconfiguration error: VM attachment to NSX or vMotion of an NSX-connected VM

Products

• VMware NSX
• VMware vSphere ESX 8.x

Issue/Introduction

• For a host which doesn't allow VM attachment to an NSX segment or subnet, or doesn't allow inward migration of an NSX-connected VM, Either vSphere vMotion shows a blocking network compatibility failure such as
  
  

  "Currently connected network interface" 'Network adapter #' uses network 'DVSwitch[## ## ## ## ## ## ## ##-## ## ## ## ## ## ## ##] NSX port group [dvportgroup-##](nsxa down)', which is not accessible.

  
  
  
• Or looking at the ESXi vpxa.log may show either:
  
  

  vim.VirtualMachine.reconfigure: :vim.fault.PlatformConfigFault
   --> message = "Failed to attach virtual network interface Unknown to logical switch ########-####-####-####-############, message from NSX: No response from NSXA"
   --> text = "Failed to attach VIF"
   --> msg = "An error occurred during host configuration: Failed to attach VIF."

  or

  vim.VirtualMachine.reconfigure: :vim.fault.PlatformConfigFault
   --> message = "Failed to attach virtual network interface Unknown to logical switch ########-####-####-####-############, message from NSX: Failed to send VIF RPC request. Please check if the connectivity between Host and NSX Manager is up."
   --> text = "Failed to attach VIF"
   --> msg = "An error occurred during host configuration: Failed to attach VIF."

   

• Or this message from NSX:
  
  

  "No response from NSXA" 
  --> text = "Failed to attach VIF" 
  --> msg = "An error occurred during host configuration: Failed to attach VIF." or vim.VirtualMachine.reconfigure: :vim.fault.PlatformConfigFault 
  --> message = "Failed to attach virtual network interface Unknown to logical switch ########-####-####-####-############
  
  "Failed to send VIF RPC request. Please check if the connectivity between Host and NSX Manager is up." 
  --> text = "Failed to attach VIF" 
  --> msg = "An error occurred during host configuration: Failed to attach VIF."

Environment

• VMware ESXi 8.x, 9.x
• VMware NSX

Cause

1. The nsxa Service is Down or Hung on the Host

The nsxa component on the ESXi host is responsible for executing network configurations. If this service crashes, hangs, or fails to start during host preparation, it cannot respond to vCenter's request to attach the VIF.

2. Host-to-NSX Manager Connectivity Issues

Even if certificates are valid and the NSX Manager appliance is stable, there could be underlying network connectivity issues (like dropped traffic or routing problems) preventing the specific ESXi host from communicating with the NSX Manager. If the host enters a "disconnected" or "failed" state in the NSX fabric, provisioning operations will fail.

3. NSX-SFHC Component Unresponsive

In the context of your specific environment, the failure to get a response from the NSX-SFHC (Service Fabric Host Component) during the cluster addition process directly leads to this nsxa timeout.

Resolution

1. Login to the NSX-Manager UI and confirm if there is any connectivity issues between the NSX-Manager and the ESXi hosts where the affected VMs are placed or are being vMotioned to.
   • Navigate to System > Fabric > Hosts
   • If any hosts are in disconnected and failed state, that has to be fixed from the NSX side.
     
     
2. For each impacted ESXi host,
   
   • ssh to the host and log in as root.
   • Check if the nsxa service is up by running:
     net-dvs -l | fgrep component.nsxa
     
     
   • If the response is: com.vmware.common.opaqueDvs.status.component.nsxa = down , propType = CONFIG
   • Then restart opsAgent by running:
     /etc/init.d/nsx-opsagent restart
     
     
   • If NSX still views the host as disconnected, then also run:
     /etc/init.d/nsx-proxy restart


3. If this doesn't resolve the issue, check the NSX Manager's certificates for expiration. If expired, replace them with valid certificates, then try resyncing or resolving the disconnected ESXi hosts.
   • If the NSX Manager's certificates are not expired, reboot the ESXi host.