Check the error logs and see what’s wrong with it instead. How is it crashing? Did you check stdout and stderr (use docker attach or check the compose logs)?
“Crash” is the wrong word. The app is running, it says “Connected” for about 15-20 seconds, then it says “Internet blocked” for about 20 seconds, then it says “Reconnecting” for 30-90 seconds, repeat indefinitely.
Using the CLI for logging, it says something along the lines of “Timeout… Hyper time out”
You should look a bit into how the internet, DNS and IP addresses work on the public internet and private networks.
Do you have any recommendations on how to learn this?
Also, thank you for explaining that “configuring a domain name” is adding an A record. I’ve added TXT records and similar for Google analytics and I’ve added mail records to set up my own domain’s email before - but this is helpful, thanks.