How to access backend API using docker-compose in App Service in Azure

Question

I am trying to make an API call to the backend. My frontend works fine, and is opened when I type firesmk.azurewebsites.net, however, my backend is not accessible at firesmk.azurewebsites.net:8080/controller/method. How would I call this? Here is my docker-compose I use in Azure:

version: '3.8'

services:
  frontend:
    image: blagojanikoloski/firesmk-frontend:latest
    container_name: firesmk-frontend
    ports:
      - "80:80"

  backend:
    image: blagojanikoloski/firesmk-backend:latest
    container_name: firesmk-backend
    ports:
      - "8080:8080"