Postfix docker image still blocking sender

Question

Trying to run a smtp relay container using boky/postfix and for testing I am trying to open up to all domains to send to the smtp relay. However, the below docker-compose.yml file for the postfix service is still denying access to all domains. Not exactly sure what is happening or why all domains are not allowed through. Am I looking at the right postfix option even? Trying to follow the documentation from the github repo located here.

I tried to enable ALLOW_EMPTY_SENDER_DOMAINS to "true" or "1" and left ALLOWED_SENDER_DOMAINS= blank or removed. This configuration seems to block me from all domains now. Is it required to set ALLOWED_SENDER_DOMAINS, and if not will postfix just block the incoming domain?

services:
  haproxy: 
    restart: unless-stopped
    image: haproxy:alpine
    networks:
      - frontend
      - backend
    ports:
      - "80:80"
      - "443:443"
      - "25:25"
    logging: 
     driver: "syslog"
    volumes:
       - ./haproxy:/usr/local/etc/haproxy:ro
    depends_on:
      - postfix
  postfix:
    restart: unless-stopped
    image: boky/postfix:latest
    logging:
     driver: "syslog"
    networks:
      - backend
    environment:
      - TZ=America/New_York
      - ALLOW_EMPTY_SENDER_DOMAINS=true
      - RELAYHOST=<o365>.outlook.com:25
      - POSTFIX_smtp_tls_security_level=may
      - POSTFIX_message_size_limit=94371840
    deploy:
       mode: replicated
       replicas: 3
    expose:
      - "25"
networks:
  frontend:
  backend: