django.db.utils.IntegrityError: UNIQUE constraint failed: authentication_user.email - django

Question

I am trying create user through an API, But i am struck on above error.
Below are the code of the User and its manager. Here, I am creating custom user model.
class UserManager(BaseUserManager):
def create_user(self,username,email, password=None):
if username is None:
raise TypeError('Users should have a Username')
if email is None:
raise TypeError('Users should have a Email')
user = self.model(username=username,email=self.normalize_email)
user.set_password(password)
user.save()
return user
def create_superuser(self,username,email, password=None):
if password is None:
raise TypeError('Password should not be none')
user = self.create_user(username, email, password)
user.save()
return user
class User(AbstractBaseUser,PermissionsMixin):
username = models.CharField(max_length=255, unique=True, db_index=True)
email = models.EmailField(max_length=255,unique=True,db_index=True)
USERNAME_FIELD = 'email'
REQUIRED_FIELDS = ['username']
objects= UserManager()
def __str__(self):
return self.email
Below is serializers.py file.
class RegisterSerializers(serializers.ModelSerializer):
password = serializers.CharField(max_length=68, min_length=6, write_only=True)
class Meta:
model = User
fields = ['email','username','password']
def validate(self, attrs):
email = attrs.get('email','')
username = attrs.get('username','')
if not username.isalnum():
raise serializers.ValidationError('The username should only contain alphanumeric character')
return attrs
def create(self, validated_data):
return User.objects.create_user(**validated_data)
Here is POST request in views.py
class RegisterView(generics.GenericAPIView):
serializer_class = RegisterSerializers
def post(self, request):
user = request.data
serializer = self.serializer_class(data=user)
serializer.is_valid(raise_exception=True)
serializer.save()
user_data = serializer.data
return Response(user_data,status=status.HTTP_201_CREATED)
I am new to drf. Kindly help me out, thanks.