Jupyter Notebook Errors

I am using Salamander and when i open a jupyter notebook the message:“internal server error” pops up.I manage to fix it by typing conda update nbconvert in the terminal, as suggested by a couple of github posts.
But then, when i actually enter a notebook, it never connects to the kernel and i cannot run any commands.I have also tried upgrading/downgrading the jupyter notebook, which didnt help either.
I’ve looked through the other forum posts and i cant find anything that solves it.
Also,i have tried this on multiple servers and its the same thing everytime.
EDIT: This happens only after a couple of starts/shutdowns of the server.When i use a newly created server, it works fine