mount.nfs4: Connection timed out error
If you get “mount.nfs4: Connection timed out” error while mounting an efs on ec2 instance, then first check the dns of your efs mountpoints. If they all are correct then issue might be due to the misconfiguration of security groups.
You need to configure two security groups, one for your ec2 instance and another for efs.
Add a rule to the EC2 security group to allow inbound access. Allow ports for ssh (22), http (80), https (443), etc. Optionally, you can restrict the source address.
Add a rule to the mount target security group to allow inbound access from the EC2 security group as:
Port Range: 2049
After above steps, try re-mounting the efs.