RabbitMQ not working when services are dockerized

So I have 2 services. Kweet (which is a tweet) and User. When I run the 2 services manually + rest of the services in docker, it works. Rest of services include MongoDB, RabbitMQ, Spring Cloud Gateway, Eureka Discovery. But the moment I run the 2 (micro)services in Docker (I just use a docker compose), the rabbitmq functionality stops working. The normal API calls work, it’s specifically the RabbitMQ calls that fail.

RabbitMQ functionality:

EditUsername, edits username in user-service. 
Than sends data via RabbitMQ (this is where it goes wrong I think) to kweet-service where it edits the username of a kweet.

Docker-compose file:

version: '3.8'

services:
  eureka-service:
    build: ./eureka-discovery-service
    restart: always
    container_name: eureka-service
    ports:
      - 8087:8087

  api-gateway:
    build: ./api-gateway
    restart: always
    container_name: api-gateway
    depends_on:
      - eureka-service
    ports:
      - 8080:8080

  user:
    build: ./user
    restart: unless-stopped
    container_name: user-ms
    ports:
      - 8081:8081
    depends_on:
      - eureka-service

  kweet:
    build: ./kweet
    restart: unless-stopped
    container_name: kweet-ms
    depends_on:
      - eureka-service
    ports:
    - 8082:8082

  mongodb:
    image: mongo
    restart: always
    container_name: mongodb
    ports:
      - 27017:27017

  rabbitmq:
    image: rabbitmq:management
    restart: always
    container_name: rabbitmq
    hostname: rabbitmq
    ports:
      - 5672:5672
      - 15672:15672

When I try to make a call the console shows:

user-ms  |  2022-04-27 08:52:04.823  INFO 1 --- [nio-8081-exec-4] o.s.a.r.c.CachingConnectionFactory : Attempting to connect to: [localhost:5672]

The postman status I get back is 503 Service Unavailable which isn’t from any try-catch‘s I made. Anybody have any clue where the problem might be?

EDIT[ConnectionFactory]:
I tried to use the documentation and added a the CachingConnectionFactory but it had the same result. Am I doing it wrong?
I added this to the RabbitMQ/Message-config (HOST, USERNAME, PASSWORD come from application.properties:

@Bean
    public AmqpTemplate template() {
        CachingConnectionFactory connectionFactory = new CachingConnectionFactory(HOST);
        connectionFactory.setUsername(USERNAME);
        connectionFactory.setPassword(PASSWORD);
        final RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
        rabbitTemplate.setMessageConverter(converter());
        return rabbitTemplate;
    }

EDIT [docker-compose]:
Found this source (https://www.linkedin.com/pulse/binding-your-docker-app-container-rabbitmq-phani-bushan/) that got rid of my 503 Service Unavailable error. The problem I found now is that whenever I start up the containers, it generates new queues and exchanges that aren’t the ones I set up in my application.properties.

Now whenever I make a call, it shows this log:

user-ms | 2022-04-28 07:36:28.825  INFO 1 --- [nio-8081-exec-1] o.s.a.r.c.CachingConnectionFactory : Created new connection: rabbitConnectionFactory#2ca65ce4:0/SimpleCo
nnection@7e7052f [delegate=amqp://[email protected]:5672/, localPort= 43208]

Things tried:

• change host to [rabbitmq-container-name] in code via CachingConnectionFactory
• change host to [rabbitmq-container-name] in docker compose with environment: - spring_rabbitmq_host=[rabbitmq-container-name]

  build: ./user
  restart: unless-stopped
  container_name: user-ms
  depends_on:
    - eureka-service
    - rabbitmq
  ports:
    - 8081:8081
  environment:
    - spring_rabbitmq_host=[rabbitmq-container-name]

• Instead of [rabbitmq-container-name] I’ve tried host.docker.internal and localhost