"No such host is known" error while using multi bots in BP

I am facing one blocker here. I have followed ur steps to create multi bots in BP
.1) Created Windows 7-virtualbox
2) Disabled firewall on both the machines
3) When opened Blueprism on local machine and virtual machine.

Only one is being connected and the other is not connecting with an error-"No such host is known"

Can anyone help to resolve....