I've never seem the Nw service shuts down like this. Is this any error in the event logs?

Has backup ever worked on this machine? Is there any firewall in the network? Is there any firewall software installed, like Windows firewall?

This is a new server included in NetWorker.
There is not firewall or firewall software installed.

There as re a few things you can try:

1. Reinstall the client.
2. Start nsrexecd with -s option.

Do the server initiated backups work properly?

I have reinstalled the clien but the problem is still the same.
When I run a server-initiated backup, the backup doesn't finish, and the nsrexecd service stops working.
I ran a save command, but instead of the -g option, I created a file with the savesets and used the -I option, and it did work.
I'm going to check network and the configuration of the group.

You can run save command directly with -s command itself. Something like: save -s {backupserver} c:

Anyway, if the client initiated backup is working, why don't you also recheck:

1. The hosts file is properly updated on both the client and the server.
2. The servers file on the client has the host name of the server. If you need to put it in now, you must restart services to make ti effective.
3. Add Client IP, Hostname & fqdn in aliases attribute of the client resource.
4. Add servers, IP or host name in the Server Network Interface attribute of the client resource.

I think this should resolve the problem.

Do you get any funny message in event log perhaps?