NFS client support on SLES 11 SP4 AMI

I deployed a SUSE Linux Enterprise Server 11 SP4 (PV, 64-bit, SSD-Backed) AMI provided by AWS / SUSE. I chose the free t1.micro instance to play around with. I have to use SLES 11 SP4.

I am trying to mount our Elastic File System via NFS and mount just hangs:

mount -t nfs4 -o rsize=1048576,wsize=1048576,hard,timeo=600,retrans=2 efs

This link says that NFS v4.0 is supported:

In my own office, I can successfully mount NFS v4.0 shares from my SLES 11 SP4 server. Is this a security issue that I am blind to?

I quickly solved this issue by changing the security group of my instance to match the security group of my file system.