The root password for NSX manager appliance has been expired.
Environment
NSX-T 4.1
Resolution
To reset the root password of NSX manager, you need to follow the steps described in the document below. If you have forgotten the current root password, you can reset it by editing the GRUB boot menu after rebooting NSX manager appliance.
The new root password will be synced with other two NSX managers in the cluster automatically.
You need to wait for a couple of minutes before NSX manager UI and API will be back. However, this is only for management plane and no impact for data plane.