I am trying to authenticate the the USER model for Register and Login API in Django REST framework. I am getting the following error msg

"detail": "Authentication credentials were not provided."

I have tried all the available internet solutions, added the

REST_FRAMEWORK = {
    'DEFAULT_AUTHENTICATION_CLASSES':(
        'knox.auth.TokenAuthentication',
        'rest_framework.authentication.TokenAuthentication',
        'rest_framework.authentication.BasicAuthentication',
        'rest_framework.authentication.SessionAuthentication',
    ),
    'DEFAULT_PERMISSION_CLASSES': [
        'rest_framework.permissions.IsAdminUser',
        'rest_framework.permissions.IsAuthenticated',
    ]
}

But nothing worked in my favor. I am adding the serilizers.py and api.py files below. Please review them and tell me if there is some other way to fix this. Following is the serializers.py file code

from rest_framework import serializers
from django.contrib.auth.models import User
from django.contrib.auth import authenticate

# User Serializer
class UserSerializer(serializers.ModelSerializer):
  class Meta: 
    model = User
    fields = ('id', 'username', 'email')

# Register Serializer
class RegisterSerializer(serializers.ModelSerializer):
  class Meta:
    model = User
    fields = ('id', 'username', 'email', 'password')
    extra_kwargs = {'password': {'write_only': True}}

  def create(self, validated_data):
    user = User.objects.create_user(validated_data['username'], validated_data['email'], validated_data['password'])

    return user

# Login Serializer
class LoginSerializer(serializers.Serializer):
  username = serializers.CharField()
  password = serializers.CharField()

  def validate(self, data):
    user = authenticate(**data)
    if user and user.is_active:
      return user
    raise serializers.ValidationError("Incorrect Credentials")

api.py is given as:

from rest_framework import generics, permissions
from rest_framework.response import Response
from knox.models import AuthToken
from .serializers import UserSerializer, RegisterSerializer, LoginSerializer

# Register API
class RegisterAPI(generics.GenericAPIView):
    serializer_class = RegisterSerializer
  
    def post(self, request, *args, **kwargs):
        serializer = self.get_serializer(data=request.data)
        serializer.is_valid(raise_exception=True)
        user = serializer.save()
        _, token = AuthToken.objects.create(user)[1]
        return Response({
        "user": UserSerializer(user, context=self.get_serializer_context()).data,
        "token": token
    })

# Login API
class LoginAPI(generics.GenericAPIView):
  serializer_class = LoginSerializer

  def post(self, request, *args, **kwargs):
    serializer = self.get_serializer(data=request.data)
    serializer.is_valid(raise_exception=True)
    user = serializer.validated_data
    _, token = AuthToken.objects.create(user)
    return Response({
      "user": UserSerializer(user, context=self.get_serializer_context()).data,
      "token": token
    })

# Get User API
class UserAPI(generics.RetrieveAPIView):
  permission_classes = [
    permissions.IsAuthenticated,
  ]
  serializer_class = UserSerializer

  def get_object(self):
    return self.request.user

Urls.py

from django.urls import path, include
from .api import RegisterAPI, LoginAPI, UserAPI
from knox import views as knox_views

urlpatterns = [
  path('api/auth/', include('knox.urls')),
  path('api/auth/register', RegisterAPI.as_view()),
  path('api/auth/login', LoginAPI.as_view()),
  path('api/auth/user', UserAPI.as_view()),
  path('api/auth/logout', knox_views.LogoutView.as_view(), name='knox_logout')
]

Please help me solve the issue. I am unable to make any post request on Postman and without Register, Login API won't work too.

To make the API public, you need to override your permissions in your settings. You should update your Views.

from rest_framework.permissions import AllowAny

# Register API
class RegisterAPI(generics.GenericAPIView):
    serializer_class = RegisterSerializer
    permission_classes = [AllowAny]
    authentication_classes=() # To make sure no check if you send Authorization header to server
    ...

Apply for your Login view too.