I cannot change all setting of Plone 6.0.6

Hello everyone.

I succeeded in getting my Plone 6.0.6 installation up and running. But now I have a new problem that I can't seem to solve. Please help me out.

The problem is that I cannot change any settings. I am Japanese, and even if I change the language to Japanese, it does not change from the default English. All other changes are not working as well. I tried the save button on the top left, but it doesn't work.

I have no idea what the problem is. I posted my environment and docker-compose.yml for your reference; I have access to Plone configured with Apache.

I would appreciate any advice you can give me.

version: "3"
services:

  frontend:
    image: plone/plone-frontend:latest
    environment:
      RAZZLE_INTERNAL_API_PATH: http://backend:8080/Plone
      RAZZLE_API_PATH: https://sub.example.com
    ports:
    - "3000:3000"
    depends_on:
      - backend

  backend:
    image: plone/plone-backend:6.0.6
    environment:
      SITE: Plone
      TYPE: volto
    volumes:
      - data:/data
    ports:
    - "8080:8080"

volumes:
  data: {}