A good way to test the app is up and running is to run docker logs 27e4c9edd311 where 27e4c9edd311 is the docker container id, which is found by running docker ps|grep fusionauth.
If you are using docker-compose, you can also run docker-compose logs -f fusionauth.
Look in the logs for any errors. On successful startup, you'll see this message (with perhaps a different version message):
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------------------------------- Starting FusionAuth version [1.16.0-RC.1] -------------------------------
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