• If NSX Manager is having connectivity issues, either with the vCenter Server or the ESXi host, log in to the NSX Manager command-line interface console and run the debug connection <IP-of-ESXi-or-VC> command and examine the output. For more information, see Network Port Requirements for VMware NSX for vSphere 6.x (2079386) at http://kb.vmware.com/kb/2079386.

• Verify that the Virtual Center Web management services is started and the browser is not in an error state. For more information, see Clicking NSX Home in the vSphere Web Client reports the error: NSX Manager Internal Error. Review the NSX Manager log for details or contact your administrator - Unexpected Status Code 503 (2091369) at http://kb.vmware.com/kb/2091369.

• Verify which port group and uplink NIC is being used by the NSX Manager using the esxtop command on the ESXi host. Attempt to migrate the NSX Manager to another ESXi host as part of the troubleshooting. You can also check the NSX Manager virtual machine appliance Tasks and Events tab from the vSphere Web Client under the Monitor tab.

• If the NSX Manager is having connectivity issues with the vCenter Server, migrate the NSX Manager to the same ESXi host where the vCenter Server virtual machine is running to eliminate possible underlying physical network.