Trying to verify a user with Django email confirmation, however some user's are getting this error when they try to confirm their email

I asked a variant of this question before, but realized I was very unclear. This is my attempt at doing a better job of explaining the issue.

I send a link to a user's email to confirm sign-up after they have registered for the site. However, a small proportion of users are getting the following error when they try to confirm their email.

Error:

TypeError/activate/{uidb64}/{token}/
error
'AnonymousUser' object is not iterable

I think the problem is that the activate function is not recognizing them. However, not sure how to make this activation link work if I send them back to the login page. Any ideas?

Do I need to add something like 'if not user.is_authenticated:' then send redirect to login? But, how do I come back to activate function? Login is general in my app to all situations.

Activate code:

try:
    uid = force_text(urlsafe_base64_decode(uidb64))
    user = User.objects.get(pk=uid)
except(TypeError, ValueError, OverflowError, User.DoesNotExist):
    user = None
if user is not None and account_activation_token.check_token(user, token):
    .... do something
else:
    return HttpResponse('Activation link is invalid!')

Here is where I create the email:

def activation_email(request):
    if request.user.is_authenticated:
        user=request.user
        message = render_to_string('email.html', {
                'user':user,
                'token':account_activation_token.make_token(user),
                'uid':urlsafe_base64_encode(force_bytes(user.pk)),
        })
        ....send mail
    else:
        return redirect('somewhere_else')

EDIT>: It's failing when I try to update my model with the email verification info:

if user is not None and account_activation_token.check_token(user, token):
      object, created = User_Profile.objects.get_or_create(
            user=request.user,
            ## This is where it fails
            email_validated=True,
        )