启动 Jupyter 笔记本时出现 500 内部服务器错误

Question

I currently decided to re-install jupyter since the kernel was continuously stopping. After having conda uninstalled ipykernel and re-installed it back, I incurred in a series of issues:

1. First once I opened the notebooks on jupyter a 500 internal error occurred;
2. Second I tried to re-install nbconvert as suggested in some issues on the topic but nothing changed;
3. third I tried to conda re-install jupyter but now even jupyter command is not working

I am currently on Mac OS Catalina Version 10.15.7. I have done a conda list and apparently everything is installed on the (base) environment where I am operating, namely:

ipykernel                 6.15.2                   pypi_0    pypi
...
jupyter                   1.0.0            py38hecd8cb5_8  
jupyter-client            7.3.5                    pypi_0    pypi
jupyter-console           6.4.4                    pypi_0    pypi
jupyter-telemetry         0.1.0                    pypi_0    pypi
jupyter_client            7.3.4            py38hecd8cb5_0  
jupyter_console           6.4.3              pyhd3eb1b0_0  
jupyter_core              4.10.0           py38hecd8cb5_0  
jupyter_server            1.13.5             pyhd3eb1b0_0  
jupyterhub                2.3.1                    pypi_0    pypi
jupyterlab                3.3.2              pyhd3eb1b0_0  
jupyterlab-pygments       0.2.2                    pypi_0    pypi
jupyterlab-widgets        3.0.3                    pypi_0    pypi
jupyterlab_server         2.10.3             pyhd3eb1b0_1  
jupyterlab_widgets        1.0.0              pyhd3eb1b0_1  

...
nbconvert                 7.0.0                    pypi_0    pypi

Am I doing something wrong? How can I solve the issue with all the needed packages up to date?

EDIT: Furthermore when I type simple commands such as conda list the following appears:

(base) MacBook-Pro-di-federico:Dropbox federiconutarelli$ conda list
Error processing line 1 of /Users/federiconutarelli/opt/anaconda3/lib/python3.8/site-packages/matplotlib-3.5.2-py3.8-nspkg.pth:

  Traceback (most recent call last):
    File "/Users/federiconutarelli/opt/anaconda3/lib/python3.8/site.py", line 169, in addpackage
      exec(line)
    File "<string>", line 1, in <module>
    File "<frozen importlib._bootstrap>", line 553, in module_from_spec
  AttributeError: 'NoneType' object has no attribute 'loader'

Reminder of file ignored

...

before listing the packages.

Thank you

Answer 1

In my case, I had this problem (500 internal server error) since I had updated the "mistune" to the latest version.

Apparently, jupyter tasks are not compatible with "mistune" >= 2.0