Faliure of clustering with TCP

I am using jgroups 2.2.9 SP3 for my cluster consisting of 4 servers (alps,karsha,ladakh,pumori)
Here is the setting in alps (initial_hosts being set to the other 3 servers)
TCP(start_port=7880;loopback=false;send_buf_size=100000;recv_buf_size=200000):TCPPING(timeout=3000;initial_hosts=karsha[7880],ladakh[7880],pumori[7880];port_range=3;num_initial_members=3):FD(timeout=2000;max_tries=4):VERIFY_SUSPECT(timeout=1500;down_thread=false;up_thread=false):pbcast.NAKACK(gc_lag=100;retransmit_timeout=600,1200,2400,4800):pbcast.STABLE(stability_delay=1000;desired_avg_gossip=20000;down_thread=false;max_bytes=0;up_thread=false):VIEW_SYNC(avg_send_interval=60000;down_thread=false;up_thread=false:pbcast.GMS(print_local_addr=true;join_timeout=5000;join_retry_timeout=2000;shun=true):pbcast.STATE_TRANSFER(up_thread=true;down_thread=true)

I started the servers one by one .
However they don't cluster . one server sends heart bit message(are you alive message) to the other and dont get the response . hence got
[NotificationBus] [ERROR] exception is ChannelClosedException ...

however sometimes it is able to cluster. it works fine with protocol stack using UDP.