A cluster of 3 NSX Manager nodes is required when using VMware NSX in a production environment. The 3 NSX Manager nodes should be visible in the NSX UI under the System > Appliances page. If an empty pane is observed in place of one or more NSX Managers here, as seen below, the environment might be affected by this issue.
VMware NSX 4.1.1
This issue is resolved in VMware NSX 4.2.0