During Kaspersky Security for Virtualization upgrade from v4.0 to v5.0 we faced few issues which required deep troubleshooting steps. We needed to download logs from Kaspersky File Antimalware Protection and Kaspersky Network Protection appliances over SSH.
We could login to the appliances over VMware vCenter guest WEB console but not over SSH using root password even SSH port was opened.
Next step after research was to allow root user to login to the system over SSH.
[root@ksv]# cat /etc/ssh/sshd_config | grep Root
PermitRootLogin yes
After that just restart sshd service and enjoy.
service sshd restart
Hope it helps you with troubleshooting.