vCenter upgrade fails with the error: com.vmware.vim.binding.vim.fault.NotAuthenticated: The session is not authenticated.
VCF 4.x
VCF 5.x
If vCenter session is created at the beginning of the upgrade and if some pre-upgrade stage takes more than half hour to complete (for e.g., some Product API taking too long to complete the task), then subsequent calls to vCenter using the old session ID will fail with unauthenticated error.
Increase the vCenter idle session timeout to 60 minutes by performing the following steps: