Ngrok server can't connect to Tails Server

[yunxi-zhang]

Hello, I tried to run the tails server and ngrok server directly by using my own-built tails server docker image and an official ngrok docker image. However, after running them, my ngrok server can't connect to my tails server.

Below shows what I've done.

1. Created a docker image based on the dockerfile in the tails server repo and pushed to the dockerhub.
2. Created a new docker bridge network called tails-server.
3. Use the following command to run this tails server
   docker run --network tails-server -p 6543:6543 -d yunxizhang/indy-tails-server:latest tails-server --host 0.0.0.0 --port 6543 --storage-path /tmp/tail-files --log-level INFO
4. Use the following command to run the ngrok server
   docker run --network tails-server -p 4040:4040 -d wernight/ngrok:latest ngrok http tails-server:6543 --log stdout

The two containers can run successfully. If I accessed the tails server directly by using the VM's public IP + port number, I can see below information, which tells me the tails server is up and running.

However, when I hit the my ngrok's server url, I got below error.

Note: I can see the same 404:Not found information if I run the built-in docker compose file provided by the indy-tails-server repo, and hit both VM's public IP + port number and the ngrok server's url in my browser.

Can any one help here on what's missing in my steps?