ERR_CONNECTION_REFUSED occurs when accessing a public IP address in EC2 - ruby-on-rails

Question

I have created an infrastructure (application) using AWS, Docker (docker-compose), and Rails.
After launching the container in EC2 and starting the rails server, I get "ERR_CONNECTION_REFUSED" when I access the public IP address.
I would like to know how to display the application screen.
My directory structure looks like:
kthr01/
docker-compose.yml
Dockerfile
start.sh
src/
app/
bin/
....
Dockerfile
FROM ruby:2.7
ENV RAILS_ENV=production
RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
&& echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
&& apt-get update -qq \
&& apt-get install -y nodejs yarn \
&& apt-get install -y vim
WORKDIR /app
COPY ./src /app
RUN bundle config --local set path 'vendor/bundle' \
&& bundle install
COPY start.sh /start.sh
RUN chmod 744 /start.sh
CMD ["sh", "/start.sh"]
docker-compose.yml
version: '3'
services:
db:
image: mysql:8.0
command: --default-authentication-plugin=mysql_native_password
volumes:
- ./src/db/mysql_data:/var/lib/mysql
environment:
MYSQL_ROOT_PASSWORD: password
web:
build: .
command: bundle exec rails s -p 3000 -b '0.0.0.0'
volumes:
- ./src:/app
ports:
- "3000:3000"
depends_on:
- db
start.sh
#!/bin/sh
if [ "${RAILS_ENV}" = "production" ]
then
bundle exec rails assets:precompile
fi
bundle exec rails s -p ${PORT:-3000} -b 0.0.0.0
I have a screen shot of the AWS console showing the EC2 security group setup:
To run this:
Verify that the container is created in the local environment and appears correctly on localhost:3000
↓
Connect to EC2 via ssh
↓
git clone
↓
docker-compose build
↓
docker-compose up
...
web_1 | => Booting Puma
web_1 | => Rails 6.1.4.4 application starting in production
web_1 | => Run `bin/rails server --help` for more startup options
web_1 | Puma starting in single mode...
web_1 | * Puma version: 5.6.1 (ruby 2.7.5-p203) ("Birdie's Version")
web_1 | * Min threads: 5
web_1 | * Max threads: 5
web_1 | * Environment: production
web_1 | * PID: 1
web_1 | * Listening on http://0.0.0.0:3000
web_1 | Use Ctrl-C to stop
↓
Access the public IP address of EC2
↓
ERR_CONNECTION_REFUSED is displayed

Answer 1

Based on the comments.
The issue was blocked port 3000 in a security group. The solution was to allow that port.