no status message at all or email that's what's confusing me, however I have done a bit more testing the problem seems to be host name resolution, I tried to mount the backup share using mount and got:
[root@server ~]# mount -t cifs \\\\SERVER2\\SERVER_BACKUP /smb -o username=rob100763,workgroup=KARTER
mount error: could not resolve address for SERVER2: Unknown error
Not sure why sme can't find the share, all the windows machines seems to see it

So I tried adding the host name to /etc/hosts and the backup seems to be working correctly :
