Gluster volume "Mount failed. Please check the log file for more details." via glusterfs protocol - 0-fuse: first lookup on root failed (Transport endpoint is not connected)

Issue

Gluster client fails to mount a gluster volume via glusterfs protocol with this error:

# mount -t glusterfs master-0-rhgs:/rep3 /testmount
Mount failed. Check the log file  for more details.

In order to understand the resolution of this issue, we need to see the network configuration, here is an example that shows the current issue:

1) Each gluster server node (three gluster nodes : master-0, master-1 and master-2) has two network interfaces, one public and one private.

# public interfaces
10.0.15.199 master-0-rhgs

# private interfaces
172.16.3.1 master-0

2) The gluster client (that needs to access the gluster volume) has one single interface with IP "10.0.90.87" that can access the public interface of the gluster nodes, but cannot reach the private gluster network "172.16.3.0/24"

3) The gluster volume (called rep3) is configured using the name "master-0" that correspond to the private interface

Volume Name: rep3
Type: Replicate
Volume ID: c7e41b5d-d0ac-4765-90e0-cbf5fc19c963
Status: Started
Snapshot Count: 0
Number of Bricks: 1 x 3 = 3
Transport-type: tcp
Bricks:
Brick1: master-0:/mnt/data2/2   <<--- "master-0" 
Brick2: master-1:/mnt/data2/2
Brick3: master-2:/mnt/data2/2