failed_to_parse_configuration_file on rabbitmq

So I just wanted to change default username password from guest to sth else on rabbitmq but nothing works for me... this is my rabbitmq.conf

[
  {rabbit,
    [
      {default_vhost,       <<"/">>},
      {default_user,        <<"itsme">>},
      {default_pass,        <<"ok">>}
    ]
  }
].

and my docker-compose:

  rabbitmq:
    image: rabbitmq:3-management-alpine
    container_name: rabbitmq
    hostname: rabbitmq
    restart: always
    # Also tried env_file and environment variables
    # env_file:
    #     - ./docs/server/stack/dev/configs/rabbitmq/.env
    # environment:
    #   RABBITMQ_DEFAULT_USER: itsme
    #   RABBITMQ_DEFAULT_PASS: ok
    ports:
      - 5672:5672
      - 15672:15672
    volumes:
      - ./configs/rabbitmq/rabbitmq.conf:/etc/rabbitmq/rabbitmq.conf:ro
    networks:
      - rabbitmq_network

and error that i get:

    BOOT FAILED
    
    ===========
    
    Error during startup: {error,failed_to_parse_configuration_file}
    
    Application rabbitmq_prelaunch exited with reason: {{shutdown,{failed_to_start_child,prelaunch,failed_to_parse_configuration_file}},{rabbit_prelaunch_app,start,[normal,[]]}}

{"Kernel pid terminated",application_controller,"{application_start_failure,rabbitmq_prelaunch,{{shutdown,{failed_to_start_child,prelaunch,failed_to_parse_configuration_file}},{rabbit_prelaunch_app,start,[normal,[]]}}}"}

2022-01-03 11:50:58.446386+00:00 [erro] <0.130.0> Error parsing configuration:

2022-01-03 11:50:58.464588+00:00 [erro] <0.130.0>   - Syntax error in /etc/rabbitmq/rabbitmq.conf after line 1 column 1, parsing incomplete

2022-01-03 11:50:58.464617+00:00 [erro] <0.130.0> Are these files using the Cuttlefish format?

i also tried to do it as config file:

default_user = itsme
default_pass = ok
stomp.default_user = itsme
stomp.default_pass = ok
mqtt.default_user = itsme
mqtt.default_pass = ok
amqp1_0.default_user = itsme

and errors:

{rabbit_prelaunch_app,start,[normal,[]]}}

{"Kernel pid terminated",application_controller,"{application_start_failure,rabbitmq_prelaunch,{{shutdown,{failed_to_start_child,prelaunch,failed_to_read_advanced_configuration_file}},{rabbit_prelaunch_app,start,[normal,[]]}}}"}

2022-01-03 12:20:01.457976+00:00 [erro] <0.130.0> Failed to load advanced configuration file "/etc/rabbitmq/rabbitmq.config": 2: syntax error before: default_pass

For me, the issue was that the file was named with the ".config" suffix. ".config" is for the advanced configuration.

Modifying it to ".conf" resolved the issue for me.

Reference: https://www.rabbitmq.com/configure.html#config-file