Jean Zay has a specific procedure to check tensorboard logs detailed here. It essentially boils down to:
module load tensorflow-gpu/py3/2.3.0 # You can use your own env or other JZ existing envs
jupyter tensorboard enable --user
idrjupPlease note that you need to connect from the declared IP adress.
On Jupyter, if you run into an Invalid credentials error, or a Jupyter tensorboard extension error, as suggested by Rémi Lacroix, you can remove the ~/.jupyter folder (command: rm -rf ~/.jupyter) and restart the procedure from scratch. In particular, make sure you re-activate the tensorboard plugin for your user: jupyter tensorboard enable --user. It generally fixes that kind of problems.