Users are unable to assign a license to vCenter and encounter the following error:"Licenses could not be assigned to the selected vCenter systems."MangementAdapter.log logs shows below error:2026-03-24T08:33:32.086Z ERROR ManagementAdapter [ops@4413 threadId="" threadName="vcf-licensing" instanceId="58" ] [ (58) com. vmware. adapter.management. components. licensing. vcf. EntitlementMutationManager. assignEntitlementsToVc] - Login failed to VC <uuid> at <vCenter-FQDN>com. vmware. vapi. client. exception. HttpProtocolException: HTTP response with status code 503 (enable debug logging for details): no healthy upstream
VCF Operations 9.0
The issue occurs when the vAPI Endpoint service on the vCenter Server is stopped or not running.
This prevents communication required for license assignment, resulting in HTTP 503 errors.
1. Take an SSH session to the vCenter Server.
2. Check the status of the vAPI Endpoint service:
service-control --status vapi-endpoint
3. If the service is stopped, start it using:
service-control --start vapi-endpoint
Once the service is running, retry the license assignment.