keycloak: Can't see the admin console

Describe the bug

I’m using a Dockerfile for create a custom image of Keycloak as follows:

FROM quay.io/keycloak/keycloak:18.0.2 as builder

ENV KC_HEALTH_ENABLED=true
ENV KC_METRICS_ENABLED=true
ENV KC_DB=postgres
# Install custom providers
RUN curl -sL https://github.com/aerogear/keycloak-metrics-spi/releases/download/2.5.3/keycloak-metrics-spi-2.5.3.jar -o /opt/keycloak/providers/keycloak-metrics-spi-2.5.3.jar
RUN /opt/keycloak/bin/kc.sh build

FROM quay.io/keycloak/keycloak:18.0.2
COPY --from=builder /opt/keycloak/ /opt/keycloak/
WORKDIR /opt/keycloak
ENTRYPOINT ["/opt/keycloak/bin/kc.sh", "start"]

and whit this docker-compose I am able to run Keycloak:

version: "3.9"
services:

  keycloak_db:
    image: postgres
    environment:
      - POSTGRES_USER=$DB_USER
      - POSTGRES_PASSWORD=$DB_PASS
      - POSTGRES_DB=$DB_NAME
      - IGNORE_INIT_HOOK_LOCKFILE=true
    volumes:
      - ./db/:/docker-entrypoint-initdb.d/
    ports:
      - ${DB_EXTERNAL_PORT:-15432}:5432

  keycloak:
    container_name: keycloak
    # image: quay.io/keycloak/keycloak:18.0.1
    image: keycloak
    ports:
      - "${KEYCLOAK_EXTERNAL_PORT:-18180}:8080"
    environment:
      - KEYCLOAK_ADMIN=${KEYCLOAK_USER}
      - KEYCLOAK_ADMIN_PASSWORD=${KEYCLOAK_PASSWORD}
      - KC_DB=postgres
      - KC_DB_URL_HOST=$DB_HOST
      - KC_DB_URL_PORT=5432
      - KC_DB_URL_DATABASE=$DB_NAME
      - KC_DB_SCHEMA=$KEYCLOAK_SCHEMA
      - KC_DB_USERNAME=$DB_USER
      - KC_DB_PASSWORD=$DB_PASS
      - KC_HTTP_ENABLED=true
      - KC_HOSTNAME=localhost
      - KC_HOSTNAME_ADMIN=localhost
      - KC_HOSTNAME_PORT=80
      - KC_HOSTNAME_STRICT_BACKCHANNEL=true
      - KC_HOSTNAME_STRICT_HTTPS=false
      - KC_PROXY=edge
      - KC_PROXY_ADDRESS_FORWARDING=true
      - KC_KEYCLOAK_FRONTEND_URL=http://localhost:18180/
      - KC_KEYCLOAK_URL=http://localhost:18180/
      # - KC_LOG_LEVEL=debug
    depends_on:
      - keycloak_db

I can see the Keycloak homepage:

But when I try to go to the admnistration console I see a blank page:

And if I use KC_FEATURES=admin2 as further environment variable I can see something, but still not the admin console:

Version

18.0.2

Expected behavior

See the admin console

Actual behavior

Can’t see the admin console

How to Reproduce?

No response

Anything else?

No response