I have setup a replica set with 2 members and 1 arbiter. In the following log,
europa is a replica set member and mercury is the arbiter. Though all 3 instances are running, I keep getting the connection refused error.

016-03-26T23:37:03.977+0000 I REPL [ReplicationExecutor] Error in heartbeat request to mercury:27017; Location18915 Failed attempt to connect to mercury:27017; couldn't connect to server mercury:27017 (10.x.x.x), connection attempt failed
2016-03-26T23:37:05.437+0000 W NETWORK [ReplExecNetThread-1] Failed to connect to 10.x.x.x:27017, reason: errno:111 Connection refused
2016-03-26T23:37:05.437+0000 I REPL [ReplicationExecutor] Error in heartbeat request to europa:27017; Location18915 Failed attempt to connect to europa:27017; couldn't connect to server europa:27017 (10.x.x.x), connection attempt failed
2016-03-26T23:37:05.439+0000 W NETWORK [ReplExecNetThread-1] Failed to connect to 10.x.x.x:27017, reason: errno:111 Connection refused
2016-03-26T23:37:05.439+0000 I REPL [ReplicationExecutor] Error in heartbeat request to europa:27017; Location18915 Failed attempt to connect to europa:27017; couldn't connect to server europa:27017 (10.x.x.x), connection attempt failed
2016-03-26T23:37:05.439+0000 W NETWORK [ReplExecNetThread-1] Failed to connect to 10.x.x.x:27017, reason: errno:111 Connection refused
2016-03-26T23:37:05.440+0000 I REPL [ReplicationExecutor] Error in heartbeat request to europa:27017; Location18915 Failed attempt to connect to europa:27017; couldn't connect to server europa:27017 (10.x.x.x), connection attempt failed
2016-03-26T23:37:05.589+0000 I REPL [ReplicationExecutor] waiting for 4 pings from other members before syncing
2016-03-26T23:37:05.979+0000 W NETWORK [ReplExecNetThread-1] Failed to connect to 10.x.x.x:27017, reason: errno:111 Connection refused
2016-03-26T23:37:05.979+0000 I REPL [ReplicationExecutor] Error in heartbeat request to mercury:27017; Location18915 Failed attempt to connect to mercury:27017; couldn't connect to server mercury:27017 (10.x.x.x), connection attempt failed
2016-03-26T23:37:05.980+0000 W NETWORK [ReplExecNetThread-1] Failed to connect to 10.x.x.x:27017, reason: errno:111 Connection refus