DataSpell won't load certain notebooks.

I'm using DataSpell 2022.2.1. When I create a Jupyter notebook (Python). The cells won't evaluate. In particular, when I select "Run cell" from the menus, there is no effect. When I do Shift+Enter or Ctrl+Enter, there is no effect. However, this is only a problem with certain notebooks... and it hasn't always been a problem. The two notebooks I created recently are both like this, but old notebooks seem fine. Furthermore, I can run my new notebooks in a different environment (Visual Studio Code).

Also... once I close the notebook, I can't reopen it. If I double click on the notebook in the workspace pane, there is no effect (it does not load). However, once again, this is only for the most recently created notebooks... the old notebooks load and work fine.

I'm not sure what I should be looking for to correct this situation.

Thanks!