Unable to add the new host to the existing cluster

[#1]

I need to add a new host to my already configured cluster in my CDP trial version. When I'm trying to add it by cluster>add hosts, I cannot select the new host name. I'm getting  Could not connect to host in the result. 

But when I try to ssh from the terminal, I was able connect to the new host from the old host. 

(I'm using 2 azure virtual machines and I have added inbound and outbound rules to accept all ports)

[#2]

Do you have SSH running on the host? Also check forward and reverse hostname lookup.