Not able to configure NFS server on EC2 instance

I have followed mentioned steps as per given in this link “http://hunterford.me/amazon-ec2-and-nfs/”.
I am able to bring up services and also able to create exports file and update on server as below:
/var/www/test_nfs 54.169.25.131(rw,async)

Here Public IP of client=54.169.25.131
Public IP of server=54.169.124.140
Then run, exportfs -ar, which was successful. Then i have create /var/www/test_nfs directory.
Also i am able to install nfs,nfslock and rpcbind on client server. Also created /var/www/test_nfs directory in client server.
Also i have same security group fo both instances with all ports open.
But when i try to mount client server on /var/www/test_nfs i am getting below error:
mount -t nfs ec2-54-169-25-131.ap-southeast-1.compute.amazonaws.com:/var/www/test_nfs /var/www/test_nfs -v

mount.nfs: timeout set for Thu Jan 1 08:25:27 2015
mount.nfs: trying text-based options ‘vers=4,addr=172.31.8.169,clientaddr=172.31.24.143’
mount.nfs: mount(2): Permission denied
mount.nfs: access denied by server while mounting ec2-54-169-25-131.ap-southeast-1.compute.amazonaws.com:/var/www/test_nfs

Please let me know if i am doing some mistake.