Ovirt host addition failed

I've installed oVirt Node 4.2.0 in one physical server and oVirt Engine 4.2.7.5-1.el7 in another physical server. When I wanted to add host from ovirt engine administrative portal I'm getting the follwing errors - 1. When I use authenticatio with root password - Error while executing action: Cannot add Host. Connecting to host via SSH has failed, verify that the host is reachable (IP address, routable address etc.) You may refer to the engine.log file for further details. 2. When I use authentication wiht SSH publc key - Error while executing action: Cannot add Host. SSH authentication failed, verify authentication parameters are correct (Username/Password, public-key etc.) You may refer to the engine.log file for further details. Note that IP connectivity from Engine to Host is ok. I checked manaully SSH login from engine to node ip.