Answer by Peter Moore for How to remove password for Jupyter Notebooks and set token again

Hmm my config looks different.

Just remove this file and it will default to making a token

$ cat ~/.jupyter/jupyter_notebook_config.json
{
  "NotebookApp": {
    "password": "sha1:d0a89f391169:9ca771c3518f845438693b938b39703ce1104eaf"
  }