Within a cell of the jupyter notebook you try to import a package (seaborn, matplotlib, ... ) but when you run that cell you get an error "module not found"
After you have checked that it is correctly:
import seaborn AND NOT import seeborn for example)To check installation :
(base) > conda activate YourCondaEnv
(YourCondaEnv) > conda list
...
You will get the list of all the packages installed , and their "channel" (condaforge, pypi ... )
iykernel:(base) > conda activate YourCondaEnv
(YourCondaEnv) > conda install iykernel
...
(YourCondaEnv) > python -m ipykernel install --user
Start jupyter notebook it should work now !
(if not, sorry 🤗 I'm out of idea)