ERR_CONNECTION_REFUSED via localhost access

[jagder]

I have no idea my problem is fit in here "Django user community", however I tried to send question. 

I made dev environment under below.

# Container is Docker container.

I made dev environment under below.

# Container is Docker container.

background.jpg

I made 1 server for backend "Django" in container.

I made 3 server for frontend "Flask"(for test), "nodejs"(for test), "React + nodejs" in container.

From "React + nodejs" srv to "Django" srv,

I couldn't access using 'http://localhost:8040/' or 'http://127.0.0.1:8040/'( both err = ERR_CONNECTION_REFUSED )

I could access only using 'http://10.128.130.47:8040/'

From "Flask" srv or "nodejs" srv to "Django" srv,

I could access using 'http://localhost:8040/' and 'http://127.0.0.1:8040/'

Are there any limitation or setting problem in Django access via localhost(or 127.0.0.1 )?

//----------------------------------------------------

Dnago srv setting.

[settings.py]

ALLOWED_HOSTS = ['*']

INSTALLED_APPS = [

'corsheaders',

....

]

MIDDLEWARE = [

'corsheaders.middleware.CorsMiddleware',

'django.middleware.common.CommonMiddleware',

....

]

CORS_ORIGIN_ALLOW_ALL  = True

//----------------------------------------------------

version infor.

# Ubuntu 20.04.1 LTS

# Python 3.8.5

# django 3, 1, 5, 'final'

# django-cors-headers 3.7.0

# node v10.19.0

# react 17.0.1

# Flask 1.1.2

[jagder]

I have no idea my problem is fit in here "Django user community", however I tried to send question. 

I made dev environment under below.

# Container is Docker container.

//----------------------------------------------------