[Python] I have a persistent 'FOREIGN KEY CONSTRAINT failed' error with shopping cart app, is...

So I'm working with a group trying to code a kind of library. We're using django to create the web application, but I keep seeing this error occur.enter image description here

Here's the model I'm using in the cart app:

from django.db import models
from video_rental.models import Movie, CustomUser
from django.conf import settings

class CartItem(models.Model):
movie = models.ForeignKey(Movie, on_delete=models.CASCADE)
quantity = models.PositiveIntegerField(default=0)
user = models.ForeignKey(CustomUser, on_delete=models.CASCADE)
date_added = models.DateTimeField(auto_now_add=True)

def __str__(self):
return f'{self.quantity} x {self.movie.title}'


Here are the views:

from django.shortcuts import render
from django.shortcuts import render, redirect
from .models import CartItem
from video_rental.models import Movie

def movie_list(request):
movies = Movie.objects.all()
return render(request, 'myapp/index.html', {'products': movies})

def view_cart(request):
cart_items = CartItem.objects.filter(user=request.user)
return render(request, 'myapp/cart.html', {'cart_items': cart_items})

def add_to_cart(request, title):
movie= Movie.objects.get(title=title)
cart_item, created = CartItem.objects.get_or_create(movie=movie, user=request.user)
cart_item.quantity += 1
cart_item.save()
return redirect('cart:view_cart')

def remove_from_cart(request, title):
cart_item = CartItem.objects.get(title=title)
cart_item.delete()
return redirect('cart:view_cart')


def home(request):
return HttpResponse('Hello, World!')



This persistently happens in the admin panel when I'm trying to add things to a cart and save it. What should I do from here? Movie is defined in the video_rental app so I imported the model from there. I'm wondering what this Foreign Key error and how I can make it work.

I've tried resolving it by correcting the models file, (I realized that the user that was specified in the model was a user that was never defined, so I once again imported the model that was being used in the video_rental app). This didn't seem to work though.

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