Error on adding host to vCenter: Cannot contact the specified host (ESXi_hostname). The host may not be available on the network, a network configuration problem may exist, or the management services on this host may not be responding.

Products

• VMware vSphere ESXi

Issue/Introduction

On trying to add a host to the inventory, users may receive the following error on entering the root account password credentials:

"Cannot contact the specified host (ESXi_hostname). The host may not be available on the network, a network configuration problem may exist, or the management services on this host may not be responding."

 

This article is applicable for when there are no problems on accessing the ESXi.

• Host is responsive to the network.
• No network configuration issues.
• vmnics are in an up state
• ESXi is sending packets on UDP port 902
  
  tcpdump-uw -ni vmk0 udp port 902
  
  
• ESXi Web Client works normally indicating host services are good and port 443 is responsive.
• Testing connectivity from vCenter to ports 443 and port 902 on the host with command "nc -z" indicates those ports are open.
• ESXi host is not pinging from vCenter

 

vCenter logs indicate the following:

vsphere_client_virgo.log:

[2025-03-28T14:37:54.307+02:00] [ERROR] -nio-127.0.0.1-5090-exec-#### #### ##### com.vmware.vsphere.client.host.impl.HostMutationProvider          Error when validating host connection com.vmware.vim.binding.vim.fault.NoHost: Cannot contact the specified host (ESXi_hostname). The host may not be available on the network, a network configuration problem may exist, or the management services on this host may not be responding.
		at sun.reflect.GeneratedConstructorAccessor686.newInstance(Unknown Source)
		at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
		at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
		at java.lang.Class.newInstance(Class.java:442)
		at com.vmware.vim.vmomi.core.types.impl.ComplexTypeImpl.newInstance(ComplexTypeImpl.java:174)
		at com.vmware.vim.vmomi.core.types.impl.DefaultDataObjectFactory.newDataObject(DefaultDataObjectFactory.java:25)
		at com.vmware.vim.vmomi.core.soap.impl.unmarshaller.ComplexStackContext.<init>(ComplexStackContext.java:30)
		at com.vmware.vim.vmomi.core.soap.impl.unmarshaller.UnmarshallerImpl$UnmarshallSoapFaultContext.parse(UnmarshallerImpl.java:167)
		at com.vmware.vim.vmomi.core.soap.impl.unmarshaller.UnmarshallerImpl$UnmarshallSoapFaultContext.unmarshall(UnmarshallerImpl.java:105)
		...
		at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1791)
		at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
		at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1190)
		at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
		at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
		at java.lang.Thread.run(Thread.java:750)

Environment

vCenter 7.x
vCenter 8.x

Cause

Cluster is split across 2 datacenters.

The vCenter VM is now residing on an ESXi host in the secondary site, preventing the ESXi host in the primary site connecting to vCenter

Resolution

- vMotion the vCenter VM to an ESXi host to the same site of the disconnected ESXi host.
- Re-connect the ESXi host