NSX Native Load Balancer status Unknown

Products

• VMware NSX

Issue/Introduction

• The LB and associated Virtual Servers status on NSX UI is fluctuating between Unknown and Success.
• In the logs on Edge, a specific server pool for the LB VS is frequently observed going into a Down state, while the rest of the configured sever pools are stable and in an UP state:
  
  2025-10-23T12:33:35.301Z edge NSX 1772227 LOAD-BALANCER [nsx@6876 comp="nsx-edge" subcomp="lb" s2comp="lb" level="WARN"] [xxxxxx-xxxx-xxxx-xxxx-xxxxxx] HLCK: monitor xxxxxx-xxxx-xxxx-xxxxxx server: <server-IP-address>:443 change to down, code: 8)

nsxapi logs from NSX Manager:
  
  2026-01-27T10:56:01.009Z INFO INTENT-PROCESSOR-CONSOLIDATED-SERVICE-0 ConsolidatedRealizedStateServiceImpl 6186 POLICY [nsx@6876 comp="nsx-manager" level="INFO" subcomp="manager"] Updated consolidated state for intentPath:/infra/lb-pools <Pool-Name> to:UNKNOWN

Environment

VMware NSX

VMware NSX-T Data Center

Cause

• The Unknown status of the LB reflects that the agg-service (process on NSX manager) is collecting the status of the Virtual Servers. During this querying, the status becomes UNKNOWN for the LB on UI.
• If the pool remains in a DOWN status, other VS will be back to SUCCESS after the re-querying.
• If  the pool keeps switching between up and down and with the above mechanism, the status remains UNKNOWN for most of the time, since the manager is always waiting for the new status of the Pool.

Resolution

The pool member which is frequently going down needs to be fixed.