HTTP Request not returning result with nginx proxy in front

I’m now using this docker-compose.yml file for my setup. I suspect Traefik is what I need to fix for CORS.

version: "3"

services:
  traefik:
    image: "traefik"
    restart: always
    command:
      - "--api=true"
      - "--api.insecure=true"
      - "--providers.docker=true"
      - "--providers.docker.exposedbydefault=false"
      - "--entrypoints.web.address=:80"
      - "--entrypoints.web.http.redirections.entryPoint.to=websecure"
      - "--entrypoints.web.http.redirections.entrypoint.scheme=https"
      - "--entrypoints.websecure.address=:443"
      - "--certificatesresolvers.mytlschallenge.acme.tlschallenge=true"
      - "--certificatesresolvers.mytlschallenge.acme.email=${SSL_EMAIL}"
      - "--certificatesresolvers.mytlschallenge.acme.storage=/letsencrypt/acme.json"
    ports:
      - "80:80"
      - "443:443"
    volumes:
      - ${DATA_FOLDER}/letsencrypt:/letsencrypt
      - /var/run/docker.sock:/var/run/docker.sock:ro

  n8n:
    image: n8nio/n8n
    restart: always
    ports:
      - "127.0.0.1:5678:5678"
    labels:
      - traefik.enable=true
      - traefik.http.routers.n8n.rule=Host(`${SUBDOMAIN}.${DOMAIN_NAME}`)
      - traefik.http.routers.n8n.tls=true
      - traefik.http.routers.n8n.entrypoints=web,websecure
      - traefik.http.routers.n8n.tls.certresolver=mytlschallenge
      - traefik.http.middlewares.n8n.headers.SSLRedirect=true
      - traefik.http.middlewares.n8n.headers.STSSeconds=315360000
      - traefik.http.middlewares.n8n.headers.browserXSSFilter=true
      - traefik.http.middlewares.n8n.headers.contentTypeNosniff=true
      - traefik.http.middlewares.n8n.headers.forceSTSHeader=true
      - traefik.http.middlewares.n8n.headers.SSLHost=${DOMAIN_NAME}
      - traefik.http.middlewares.n8n.headers.STSIncludeSubdomains=true
      - traefik.http.middlewares.n8n.headers.STSPreload=true

    environment:
      - N8N_BASIC_AUTH_ACTIVE=true
      - N8N_BASIC_AUTH_USER
      - N8N_BASIC_AUTH_PASSWORD
      - N8N_HOST=${SUBDOMAIN}.${DOMAIN_NAME}
      - N8N_PORT=5678
      - N8N_PROTOCOL=https
      - NODE_ENV=production
      - WEBHOOK_URL=https://${SUBDOMAIN}.${DOMAIN_NAME}/
      - GENERIC_TIMEZONE=${GENERIC_TIMEZONE}
    volumes:
      - ${DATA_FOLDER}/.n8n:/home/node/.n8n
      - /local-files:/files