Unable to contact my own server

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Hello,

I have the following setup:

• Ros indigo

• -Laptop hosting a local wifi hotspot with IP 10.42.0.1. It is also connected to the internet via ethernet, but on a different network interface, so different (and unrelated IP).

• -Youbot that has joined the created hotspot (These are the only two
  things in that network). IP 10.42.0.20
• -SSH 'd into the Youbot on the mentioned Laptop.

• The .bashrc on the laptop has the following lines in it:

  export ROS_IP=10.42.0.1
  export ROS_MASTER_URI=http://10.42.0.1:11311
  

• The youbot sources the .bashrc on ssh login and it also contains

  export  ROS_IP=10.42.0.1 
  export  ROS_MASTER_URI=http://10.42.0.1:11311
  

What I can do:

• ping in either direction (always using the IP, never the hostname)
• Netcat in either direction
• Start roscore on the Laptop

What I cannot do:

• Start the youbot driver on the youbot. It always terminates with the "Unable to contact my own server at [ http://10.42.0.1:35449/]" message. I feel like I've looked at a lot of tutorials and don't see what's wrong, but there obviously is something wrong. Can anybody tell me what please?