I think that, @Hangover2 suggests to open the 27018 port because it is used in mongo DB config in manual port mapping.I have opened the firewall ports incoming/outgoing as advised.
But on your screenshot I see that you are using mapping 27017 -> 27017. In that case I think you need to open the 27017 port, not the 27018. Probably that's the reason of connection timeout.