The error message Cannot read the array length because "" is null occurs during the "Gather input for deletion of NSX component" stage of a VMware Cloud Foundation (VCF) workload domain deletion. This indicates that the SDDC Manager's workflow attempted to retrieve a list (an array) of NSX components, specifically the NSX Edge cluster associated with the workload domain, but found that the object no longer exists (is null). This happens when the NSX Edge cluster has been deleted manually through the NSX Manager UI, outside of the VCF-orchestrated workflow. SDDC Manager is unaware of this out-of-band change and fails when it cannot find the expected component in its inventory to proceed with the automated deletion.

A. The NSX Edge Cluster Deployment Removal Tool is a specific cleanup utility; while its use could cause issues, manual deletion via the UI is the direct cause of this specific null reference error.

C. Sharing an NSX Manager across workload domains is a supported and standard VCF architecture and does not, by itself, cause the deletion process to fail.

D. Network Pools are logical constructs within SDDC Manager. Deleting underlying networking from the vSphere Client would likely result in different errors at a different stage of the workflow.

1. VMware Knowledge Base, Article 83425 (2021), "Workload domain deletion fails at task 'Gather input for deletion of NSX component'".

Section: Cause

Content: "This issue occurs when the NSX-T Edge Cluster associated with the workload domain being deleted has been removed from NSX-T Manager manually." The article explicitly states that the symptom TypeError: Cannot read the array length because "" is null. is caused by this out-of-band manual deletion.

2. VMware Cloud Foundation Administration Guide (for multiple versions, e.g., 4.5, 5.0).

Section: Lifecycle Management of VMware Cloud Foundation

Content: The documentation consistently emphasizes that all lifecycle management operations for VCF components (including creation, expansion, and deletion of workload domains) must be performed exclusively through the SDDC Manager UI or API. Performing actions directly in component managers like vCenter Server or NSX Manager is unsupported and leads to inconsistencies and operational failures, as seen in this scenario.