No connection to Ryuk when running tests in Docker Compose on Ubuntu with `ufw` enabled

I'm trying to run a Docker container that spins up a test container through docker-compose and Gradle. Everything works fine in CircleCI, but it does not work on my VPS (fresh Ubuntu + Docker). CircleCI and the VPS both use the same versions:

Docker 20.10.12
Docker Compose 1.29.2
Ubuntu 20.04
Gradle 7.3

// In build.gradle.kts
implementation(platform("org.testcontainers:testcontainers-bom:1.16.3"))
implementation("org.testcontainers:mysql:1.16.3")

In Docker-compose.yml:

console_gradle:
  image: openjdk:17-jdk
  working_dir: /app/backend/console
  volumes:
    - ./app/backend:/app/backend
    - /var/run/docker.sock:/var/run/docker.sock
  entrypoint: [ './gradlew' ]

Running docker-compose:

docker-compose run console_gradle installDist

Running in build.gradle.kts:

...
> Task :core:startTestDatabase
Timed out waiting for Ryuk container to start. Ryuk's logs:
2022/02/05 21:36:35 Pinging Docker...
2022/02/05 21:36:35 Docker daemon is available!
2022/02/05 21:36:35 Starting on port 8080...
2022/02/05 21:36:35 Started!
...

The error:

...
Can not connect to Ryuk at 172.17.0.1:49153
java.net.SocketTimeoutException: Connect timed out
        at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:546)
        at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:597)
        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
        at java.base/java.net.Socket.connect(Socket.java:633)
        at org.testcontainers.utility.ResourceReaper.lambda$null$3(ResourceReaper.java:194)
        at org.rnorth.ducttape.ratelimits.RateLimiter.doWhenReady(RateLimiter.java:27)
        at org.testcontainers.utility.ResourceReaper.lambda$start$4(ResourceReaper.java:190)
        at java.base/java.lang.Thread.run(Thread.java:833)
Can not connect to Ryuk at 172.17.0.1:49153
java.net.SocketTimeoutException: Connect timed out
        at java.base/sun.nio.ch.NioSocketImpl.timedFinishConnect(NioSocketImpl.java:546)
        at java.base/sun.nio.ch.NioSocketImpl.connect(NioSocketImpl.java:597)
        at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:327)
        at java.base/java.net.Socket.connect(Socket.java:633)
        at org.testcontainers.utility.ResourceReaper.lambda$null$3(ResourceReaper.java:194)
        at org.rnorth.ducttape.ratelimits.RateLimiter.doWhenReady(RateLimiter.java:27)
        at org.testcontainers.utility.ResourceReaper.lambda$start$4(ResourceReaper.java:190)
        at java.base/java.lang.Thread.run(Thread.java:833)
...

What I've tried on the VPS:

 docker run -d -v /var/run/docker.sock:/var/run/docker.sock -p 8080:8080 testcontainers/ryuk:0.3.1

Which does succeed:

nc -zv localhost 8080
Connection to localhost 8080 port [tcp/http-alt] succeeded!

Anyone else experiencing this issue? Or does someone know a solution?

Thanks in advance! :)

Start with the Docker Compose service definition, the Gradle startTestDatabase task, and the Ryuk logs showing port 8080 and 172.17.0.1:49153. Reproduce on Ubuntu with UFW enabled, compare the successful host nc check with the container-to-Ryuk connection, and consider the issue complete when the test container can connect to Ryuk under the reported setup.