Network is unreachable. Reason: couldn't connect to server 13.55.62.12:27017, connection attempt failed: SocketException: Error connecting to 13.55.62.12:27017 :: caused by :: No connection could be made because the target machine actively refused it.

Open up mongodb config file:

Ubuntu:

sudo nano /etc/mongod.conf

Window:

MongoDB_installation_Directory/Server/{version}/bin/mongod.cfg 
// MongoDB_installation_Directory could be C://MongoDB or C://Program Files/MongoDB

Edit:

# network interfaces
net:
    port: 27017
    bindIp: 0.0.0.0   #default value is 127.0.0.1

Restart MongoDB Server:

sudo service mongod restart

By default mongodb is configured to allow connections only from localhost. We need to allow remote connections. In the config file, go to the network interfaces section and change the bindIp from 127.0.0.1 to 0.0.0.0 which means allow connections from all IP addresses.