Docker would not blockk it, but you can check if you have any firewall enabled on Debian. You can also test another command like this running on the host:
python3 -m http.server --bind 0.0.0.0 9999
And run a container with curl and access it like:
docker run --rm -it --add-host host.docker.internal:host-gateway nicolaka/netshoot
and
curl host.docker.internal:9999
If it doesn’t work, stay in the container and run:
ip a
and
cat /etc/hosts
So check the interfaces in the container and the IP of host.docker.internal in the hosts file.
Using the nicolaka/netshoot image you can run other network debug tools too.