Keycloak.x - create initial admin user fails

Hello

I’m would like to have a look at Keycloak.X (12.0.1) on Windows 10.
Keycloak.X starts up but then trying to create an admin user I get the following error message:
“An internal server error has occurred”

I don’t see any message in the console nor can I find a log file. Any Idea whats wrong or how I can enable better logging?

EDIT:
The same issue happens in version 12.0.0.
I also found configuration for logging: /conf/keycloak.properties but setting the configuration to quarkus.log.level = WARN doesn’t bring any valuable information.
EDIT:
Tested different Java Versions, same Problem:
openjdk version “1.8.0_222”
openjdk version “11.0.6”
openjdk version “14.0.2”

Same problem here on macOS 10.15.7 and JDK 11.0.4.

I have the same issue with 12.0.1 running on Fedora 33. Although the text that is displayed is “An internal server error has occurred”, the HTTP status of the response is 415, which indicates an unsupported media type (and not a server error). I’m going to try configuring https to see if that helps

Same issue on Mac 10.15.7 and JDK 11.0.9.

My temporary workaround is to use an unofficial docker image from here: https://hub.docker.com/r/rwxproject/keycloak-x

Works fine with:

docker run --name keycloak -p 8080:8080 \
    -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN_PASSWORD=admin \
    rwxproject/keycloak-x:12.0.1 \
    start-dev

This works now with new keycloak.x version 12.0.2: Keycloak - Downloads