Page not found at /register/... Raised by: my_blog.views.post_detail... Django

I'm working on Django blog, and I'm working on register form. I got error Page not found at /register/ like you can see on image. But it say that error was raised by post_detail - Raised by: my_blog.views.post_detail

This is register.html

{% extends "base.html" %}
{% load static %} 

{% block content %} 
{% load crispy_forms_tags %}         

<!--Register--> 
<div class="container py-5">
    <h1>Register</h1>
    <form method="POST">
        {% csrf_token %}
        {{ register_form|crispy }}                    
        <button class="btn btn-primary" type="submit">Register</button>
    </form>
    <p class="text-center">If you already have an account, <a href="/login">login</a> instead.</p>
</div>

{% endblock %}

Views.py

def register_request(request):
    if request.method == "POST":
        form = NewUserForm(request.POST)
        if form.is_valid():
            user = form.save()
            login(request, user)
            messages.success(request, "Registration successful." )
            return redirect("main:homepage")
        messages.error(request, "Unsuccessful registration. Invalid information.")
    form = NewUserForm()
    return render (request=request, template_name="register.html", context={"register_form":form})


def post_detail(request, slug):
    latest_posts =  Post.objects.filter(created_at__lte=timezone.now()).order_by('created_at')[:9]
    post = get_object_or_404(Post, slug=slug)

    context = {'post': post, 'latest_posts': latest_posts}
    return render(request, 'post_detail.html', context)

blog/urls.py

from . import views
from django.urls import path

urlpatterns = [
    path('', views.home, name='home'),
    path('<slug:slug>/', views.post_detail, name='post_detail'),
    path('category/<slug:slug>/', views.category_detail, name='category_detail'),
    path('register/', views.register_request, name='register'),
]

forms.py

class NewUserForm(UserCreationForm):
    email = forms.EmailField(required=True)

    class Meta:
        model = User
        fields = ("username", "email", "password1", "password2")

    def save(self, commit=True):
        user = super(NewUserForm, self).save(commit=False)
        user.email = self.cleaned_data['email']
        if commit:
            user.save()
        return user

I got this error and I don't understand why I get this error. Any ideas?

Thanks in advance!

"register" is a valid slug so the post_detail url is matching the incoming path as it's before your register url in urlpatterns.

The first option is to change post_detail to include a prefix so that it doesn't match your other urls

urlpatterns = [
    path('', views.home, name='home'),
    path('post/<slug:slug>/', views.post_detail, name='post_detail'),
    path('category/<slug:slug>/', views.category_detail, name='category_detail'),
    path('register/', views.register_request, name='register'),
]

Or you could put post_detail last so that other urls are matched first

urlpatterns = [
    path('', views.home, name='home'),
    path('category/<slug:slug>/', views.category_detail, name='category_detail'),
    path('register/', views.register_request, name='register'),
    path('<slug:slug>/', views.post_detail, name='post_detail'),
]