Fail connecting octave kernel with JupyterHub

[maucejo]

I have tried to use the octave kernel within a Jupyterhub instance. I have followed the instructions given in the ReadMe.rst. Unfortunately, when opening a new notebook, the kernel does not start. When opening a terminal, octave runs, but returns two warnings:
octave: X11 DISPLAY environment variable not set
octave: disabling GUI features

Do you have any idea to solve this problem ?

$ python -m octave_kernel.check
Octave kernel v0.32.0
Metakernel v0.27.5
Python v3.7.8 | packaged by conda-forge | (default, Nov 27 2020, 19:24:58)
[GCC 9.3.0]
Python path: /srv/conda/envs/notebook/bin/python

Connecting to Octave...
Octave connection established
Octave Kernel v0.32.0 running GNU Octave v6.1.0
Graphics toolkit: gnuplot
Available toolkits:
[1,1] = gnuplot
}

Thanks