I am trying to make a Blog, where a person adds a post by selecting its category. As I submit the post the above-said error appears.

views.py

def posts(request):
    posts = Blog.objects.all()
    context={
        'posts': posts
    }
    return render(request, 'dashboard/posts.html', context)
def add_post(request):
    if request.method == 'POST':
        form = BlogPostForm(request.POST, request.FILES)
        if form.is_valid():
            post = form.save(commit=False)
            post.author = request.user
            post.save()
            return redirect('posts')
        else:
            print('form is invalid')
            print(form.errors)
    form=BlogPostForm()
    context={
        'form': form
    }
    return render(request, 'dashboard/add_post.html', context)

models.py

class Blog(models.Model):
    title = models.CharField(max_length=100)
    slug = models.SlugField(max_length=150, blank=True, unique=True)
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    auther = models.ForeignKey(User, on_delete=models.CASCADE)
    featured_image = models.ImageField(upload_to='uploads/%y/%m/%d')
    short_description = models.TextField(max_length=500)
    blog_body = models.TextField(max_length=2000)
    status = models.CharField(max_length=20, choices = STATUS_CHOICES, default = "Draft")
    is_featured = models.BooleanField(default=False)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models. DateTimeField(auto_now=True)