Kindly note that I am able to ssh from the server to the Netexpress via passwordless connection but cannot do the same from the Netexpress to the server
[root@Storage-Relay mnt]# ssh email@example.com
Riverbed Cascade Express (virtual) 10.10 (release 20170606_1501)
Last login: Tue Dec 19 05:13:31 2017 from 1192.168.1.3
Just checking some obvious stuff, have you looked into this?
Perhaps you need to restrict the permissions so that only the user has write access to the backup directory
The issue is most likely (as you identified) a problem with the NetExpress not being able to SSH to the backup system via password-less logins. This is necessary to prevent the password being entered over and over again.
You should confirm the settings on your ~/.ssh directory and the authorized_keys file within that directory on the backup system.
It depends on the Linux release . as ~/.ssh directory permissions was fine as below
-rw-r-----. 1 root root 2562 Jan 11 05:13 authorized_keys2
anyway,for my Centos 7 the issue was resolved after doing below tuning
service sshd reload