Getting access denied from watchtower when pulling from docker hub with docker-compose

Question

I'm getting the following error from my watchtower container:

level=debug msg="Error pulling image aaa/xxx-react18-menu:latest, Error response from daemon: Head \"https://registry-1.docker.io/v2/aaa/xxx-react18-menu/manifests/latest\": unauthorized: incorrect username or password"

I've updated my docker-compose file to have the following which is how I thought I needed to add my docker hub password but I still get the error.

services:
    watchtower:
      image: index.docker.io/containrrr/watchtower:latest
      restart: always
      volumes:
        - /var/run/docker.sock:/var/run/docker.sock
        - /etc/timezone:/etc/timezone:ro
      environment:
        - WATCHTOWER_CLEANUP=true
        - WATCHTOWER_LABEL_ENABLE=false
        - WATCHTOWER_INCLUDE_RESTARTING=true
        - WATCHTOWER_DEBUG=true
        - WATCHTOWER_POLL_INTERVAL=45
        - REPO_USER='mydockerusername'
        - REPO_PASS='mydockerpassword'
        
      labels:
        - "com.centurylinklabs.watchtower.enable=true"

How can I get my credentials from docker-compose watchtower to docker hub?