While restoring NSX-T Manager 4.x you may encounter the following error messages:
"Error: upstream connect error or disconnect/reset before headers. reset reason: connection termination (Error code: 503)"
The above error may disappear after a while. Restore process will continue and then it will get stuck at Restore process failed, as show below:
Error copying inventory backup file from/to remote/local server: {/upload/NSX-ESX-R/inventory-summary/4.0.0.1.0.20159694-<UUID>-<IP Address>/inventory-<date&time>UTC.json=/image/backup/cluster/inventory_backup.json}.
No resolution available at this time.
Please follow workaround process.
Workaround:NSX-T Manager cannot be restored.