Follow following step to work genemotion.
Open Oracle VM virtual Box
File -> Preferences ( ctrl + g ) -> open one dialog box -> select Network -> select Host only network choose you adapter ( there are three button on right side -add -remove -Edit host only nw.,
If you dont have any adapter then create.
After selecting your adapater choose Edit Edit host only network(space)
Open one dialog box then choose DHCP server choose Enable Server and fill all ip addresses.
like
IPv4 address/netmask: 192.168.56.1/255.255.255.0 (on Adapter tab)
DHCP server enabled checked (on DHCP server tab)
Server address/netmask: 192.168.56.100/255.255.255.0
Server lower/upper address: 192.168.56.100/192.168.56.254
Give ok.
In starting of the oracle virtual machine there are different tab like General ,system , Display ,storage,Network etc.. Click on Network
Open one dialog box, select Enable Network adapter attached to ->host only network
and main thing is that in Name tab, choose adapter that you are choosing in preference both adapter much be match example you choose virtualbox...2 then here also choose that one.
Ok.