Cannot connect to docker image with localhost port mapping

I am trying to build a reusable docker image for NLP data projects. I have built a Dockerfile in the following way:

FROM python:3.8

COPY requirements.txt .
RUN pip install -r requirements.txt

ENV PYTHON_PACKAGES="\
    numpy \
    matplotlib \
    scipy \
    scikit-learn \
    pandas \
    nltk \
    wordcloud \
    spacy \ 
" 

RUN pip install -r requirements.txt
RUN pip install jupyter

CMD ["jupyter", "notebook", "--allow-root"]

Note that the docker image composes correctly with all of my dependencies in the requirements file. However, when I attempt to connect on the local host, my attempt is rejected. I ran the container using the following:

docker run -dp 9999:9999 tdnlptools

I validated that the container is running:

CONTAINER ID   IMAGE        COMMAND                  CREATED         STATUS         PORTS                    NAMES
c26b647a1403   tdnlptools   "jupyter notebook --…"   7 seconds ago   Up 6 seconds   0.0.0.0:9999->9999/tcp   modest_mcnulty

Yet, when I attempt to use the following connection, it won't work:

https://localhost:9999/

The error is:

This site can’t be reached
localhost unexpectedly closed the connection.

Try:

Checking the connection
Checking the proxy and the firewall
ERR_CONNECTION_CLOSED

Any idea why my connection is being refused?

source https://stackoverflow.com/questions/72664099/cannot-connect-to-docker-image-with-localhost-port-mapping