ECS Docker container won't start - amazon-web-services

Question

I have a Docker container with this Dockerfile:
FROM node:8.1
RUN rm -fR /var/lib/apt/lists/*
RUN echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee /etc/apt/sources.list.d/webupd8team-java.list
RUN echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main" | tee -a /etc/apt/sources.list.d/webupd8team-java.list
RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
RUN apt-get update
RUN echo debconf shared/accepted-oracle-license-v1-1 select true | \
debconf-set-selections
RUN echo debconf shared/accepted-oracle-license-v1-1 seen true | \
debconf-set-selections
RUN apt-get install -y oracle-java8-installer
RUN apt-get install -y openssh-server
RUN mkdir /var/run/sshd
RUN mkdir -p /app
WORKDIR /app
# Install app dependencies
COPY package.json /app/
RUN npm install
# Bundle app source
COPY . /app
# Environment Variables
ENV PORT 8080
# start the SSH daemon service
RUN service ssh start
# create a non-root user & a home directory for them
RUN useradd --create-home --shell /bin/bash tunnel-user
# set their password
RUN echo 'tunnel-user:93wcBjsp' | chpasswd
# Copy the SSH key to authorized_keys
COPY tunnel.pub /app/
RUN mkdir -p /home/tunnel-user/.ssh
RUN cat tunnel.pub >> /home/tunnel-user/.ssh/authorized_keys
# Set permissions
RUN chown -R tunnel-user:tunnel-user /home/tunnel-user/.ssh
RUN chmod 0700 /home/tunnel-user/.ssh
RUN chmod 0600 /home/tunnel-user/.ssh/authorized_keys
# allow the tunnel-user to SSH into this machine
RUN echo 'AllowUsers tunnel-user' >> /etc/ssh/sshd_config
EXPOSE 8080
EXPOSE 22
CMD [ "npm", "start" ]
My ECS task has this definition. I'm using a role which has AmazonEC2ContainerServiceforEC2Role.
When I try to start it as a task in my ECS cluster I get this error:
CannotStartContainerError: API error (500): driver failed programming external connectivity on endpoint ecs-ssh-4-ssh-8cc68dbfaa8edbdc0500 (387e024a87752293f51e5b62de9e2b26102d735e8da500c8e7fa5e1b4b4f0983): Error starting userland proxy: listen tcp 0.0.0
How do I fix this?