Elastic Cluster node problem

Hi,
I am new to elsticsearch. I just downloaded the free version of elasticsearch. I have installed them in two servers: node1 and node 2. I have same elasticConfig the only difference is the node as following:

node1:
cluster.name: mccluster.domain.com
transport.tcp.port: 9300
http.port: 9200
network.host: MyIP
node.master : true
node.data: false
discovery.zen.ping.unicast.hosts: list of nodes
node.name: node1

node2:
cluster.name: mccluster.domain.com
transport.tcp.port: 9300
http.port: 9200
network.host: MyIP
node.master : false
node.data: true
discovery.zen.ping.unicast.hosts: list of nodes
node.name: node2

However, when I run a any node it faisl with cannot discover master.
Any idea?

There's not much information to go on here. It'll be much easier to help if you share some of the log messages you're seeing.