VPS backup/migration task in OA fails with the following diagnostics:
-1: Connect failed:
This error occurs if PVA agent service on the Virtuozzo server with the container cannot establish data connection to the target node over the port 4435.
Use tcpdump/windump (or Microsoft Network Monitor) tools on source hardware node to check if packets are reaching the target server. Check/configure firewall rules on PVC server in accordance with KB articles:
Virtuozzo for Linux - Which ports should be opened on Virtuozzo hardware node and Service Container
Virtuozzo for Windows - Which ports should be opened on Virtuozzo hardware node and Service VE