as a note I give you the tips not to forget :
* read the ROS wiki ! 🙂 and especially this : http://wiki.ros.org/ROS/NetworkSetup
the most important thing is that both machines need their hostname to be known by each-other => /etc/hosts
and verify it by doing a ping [other machine hostname]
* check the niryo ROS_MASTER_URI is set with current niryo hostname (eg: ROS_MASTER_URI=http://niryo-desktop:11311)
and set the one on the remote machine with the SAME : export ROS_MASTER_URI=http://niryo-desktop:11311 to tell where the ROS master is !
(I end up with putting it into my .bashrc to always have it fixed when I launche a new terminal (export ROS_MASTER_URI=http://22.214.171.124:11311