Not sure what your fly.toml looks like, but by default there is a health check configuration in place. In the logs you shared above, you can see Health Checks = 1 total, 1 critical – this means there was a health check issue. I’d recommend looking into whether your app is configured correctly to receive and respond to the health check. Your Dockerfile is set to expose 8080, but is there any code responding to health check requests?
If you’re running an app that doesn’t need a health check, it’s also possible to disable it.