Getting [unable login] error in DRF login api

Question

Hi I am creating a login api in django restframework, but i got error wile test api in postman getting error Unable to login i have trying mutiple way can't solve this error

models.py

class GmsUser(GmsBaseModel):
    first_name=models.CharField(max_length=255,null=True, blank=True)
    middle_name=models.CharField(max_length=255,null=True, blank=True)
    last_name=models.CharField(max_length=255,null=True, blank=True)
    user_name=models.CharField(max_length=255,null=True, blank=True, unique=True)
    password=models.CharField(max_length=255,null=True, blank=True)

views.py

@csrf_exempt
@api_view(["POST"])
@permission_classes((AllowAny,))
def gms_user_login(request):
    if request.method == 'POST':
        user=authenticate(
            request,
            user_name=request.data['user_name'],
            password=request.data['password']
        )
        users=GmsUser.objects.filter(user_name=request.data['user_name']).values_list('id',flat=True)
        query=GmsUserRole.objects.filter(user=users[0]).exists()      
        if user is None:
            return JsonResponse({'error':'unable to login'}, status=400)
        else:
            try:
                if query:
                    token = Token.objects.get(user=user)
                    return JsonResponse({'token': token.key}, status=201)
                else:
                    return JsonResponse({'error':'User does not have role'}, status=400)
                
            except Token.DoesNotExist:
                token = Token.objects.create(user=user)
                return JsonResponse({'token': str(token)}, status=200)