v2t: Import-configuration Failed with "General error"

Products

• VMware NSX

Issue/Introduction

• On Phase 1 --Import Configuration , When you click START button an error prompts : 
  
  General error has occurred. 
  
  
• In the var/log/migration-coordinator/migration-coordinator.log , you see entries similar to:
  
  2021-04-05T20:37:01.420Z ERROR http-nio-127.0.0.1-7450-exec-1 NsxBaseRestController 15343 SYSTEM [nsx@6876 comp="nsx-manager" errorCode="MP100" level="ERROR" subcomp="migration-coordinator"] 0 java.lang.ArrayIndexOutOfBoundsException: 0

2021-04-05T20:37:01.421Z INFO http-nio-127.0.0.1-7450-exec-1 NsxBaseRestController 15343 SYSTEM [nsx@6876 audit="true" comp="nsx-manager" level="INFO" subcomp="migration-coordinator"] UserName:'admin' ModuleName:'common-services' Operation:'POST@/api/v1/migration/plan' Operation status: 'failure' Error: General error has occurred.
  
  Note: The preceding log excerpts are only examples. Date, time, and environmental variables may vary depending on your environment.
  

Environment

VMware NSX-T Data Center 3.x

Cause

Import-configuration Failed with "General error" when any ESXI  connectionState ≠ connected in VC , regardless if its NSX prepared.

Resolution

Find all  the discovered objects from VC on the NSX-T Manager using this API and check if any host  connectionState ≠ connected.

Such as  disconnected  or notResponding

curl -k -H "Content-Type:application/json" -u admin -X GET https://localhost/api/v1/fabric/discovered-nodes

Example of truncated API response : 

Workaround:
Ensure that all host are either connected to VC or removed from VC.