AxiosError: Network Error in React Native and Django

I am new in Django and React Native.

Im using Django rest framework to connect my front end to backend. and I am using

"axios"

in sending request to django

I am trying send URL in django. After receiving, the django will give the length of the url as a response to the react native.

I access the path of django in my browser and I think it works fine

However, the react native shows "[AxiosError: Network Error]". Your help is deeply appreacited.

React Native

It sends URL to django

  const [countChar, setcountChar] = useState()

  const sendData = async() =>{

      const url = "Hello"
      
        const response = await axios.post(
          'http://127.0.0.1:8000/validationServer/validate/',
          { url }
        );

        setcountChar(response.data.character_count);
        console.log(countChar)
        
  }

 <TouchableOpacity
              style={{backgroundColor:"white" ,padding:20}}
              onPress={ () => sendData()}>

                 <Text>Send</Text>
  </TouchableOpacity>

validationServer/ view.py

from rest_framework.decorators import api_view
from rest_framework.response import Response
from .serializer import UrlSerializer

@api_view(['POST'])
def validation (request):

    if request.method == 'POST':
        serializer = UrlSerializer(data=request.data)
        if serializer.is_valid():
            url = serializer.validated_data['url']
            character_count = len(url)
            return Response({'character_count': character_count})
        return Response(serializer.errors, status=400)

validationServer/ serializer.py

from rest_framework import serializers

class UrlSerializer(serializers.Serializer):
    url = serializers.CharField(max_length=2048)  

validationServer /urls.py

from django.urls import path
from . import views

urlpatterns = [

    path ("validate/",views.validation, name='url-character')
]

// main / urls.py

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path("admin/", admin.site.urls),
    path('api-auth/', include('rest_framework.urls')),
    path("validationServer/", include('validationServer.urls'))
]

//setting.py

ALLOWED_HOSTS = [
"127.0.0.1"
    ]

INSTALLED_APPS = [
    "django.contrib.admin",
    "django.contrib.auth",
    "django.contrib.contenttypes",
    "django.contrib.sessions",
    "django.contrib.messages",
    "django.contrib.staticfiles",
    "validationServer",
     "corsheaders",
    'rest_framework',
    
]

MIDDLEWARE = [
    "django.middleware.security.SecurityMiddleware",
    "django.contrib.sessions.middleware.SessionMiddleware",
    "django.middleware.common.CommonMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    "django.contrib.auth.middleware.AuthenticationMiddleware",
    "django.contrib.messages.middleware.MessageMiddleware",
    "django.middleware.clickjacking.XFrameOptionsMiddleware",

        "corsheaders.middleware.CorsMiddleware",
    "django.middleware.common.CommonMiddleware",

]