VPS backup task fails in POA with the following diagnostics:
422 : Failed to connect to backup server: Can't perform SSL connection: (null)
VZAgent on the target node does not respond properly over the port 4434, probably the installation is corrupted. Could be also resource shortage on the source server, it might be unable to initialize structures necessary for SSL connection establishment.
Check if VZAgent service is up and running on target PVC server, try to restart it.
Check resources on source PVC server - look at least at messages in the file
Execute the command on source PVC server and check its output for error messages:
~# openssl s_client -connect TARGET_SERVER:4434 -cipher ADH-AES256-SHA
The problem might occur due to high handles usage on PVC server.
Run Task Manager, select tab Processes, add Handle count (or similar) in View -> Select columns menu. Sort by the column Handles and check which process in which container uses a lot of handles. The normal usage is about 30-40k handles (reasonable maximum), anything above is the subject to investigate closer, especially if the usage of handles is above 100k.
The proper solution is to report the high usage (possible handles leak) to the corresponding software vendor if process consuming a lot of handles is working inside a container. In the matter of Virtuozzo, the only way is to solve the problem is to restart the 'faulty' application in the container to have the node operating in the normal way.
If process which consumes too many handles is a part of PVC then report problem to PVC development team.