Invalid filter: 'markdown' django-markdown-deux

[ZixiSu]

Before I explain my issue, let me tell you some basics of my system: windows 10 python 3.6 django 1.9

I followed the documention of 'django-markdown-deux', from it, I learned it has four steps to be implemented.
Firstly: pip3 install django-markdown-deux
Secondly: add 'markdown_deux' into your INSTALLED_APP
Thirdly: add {% load markdown_deux_tags %} into your header.html
Finally: add {{ post.body|markdown }}, as I want to transfer post.body to markdown

{% extends "personal/header.html" %}
{% block content %}

<h3><a href="/blog/{{post.id}}">{{ post.title }}</a></h3>
<h6> on {{ post.date }}</h6>

<div class = "container">
	{{ post.body|markdown }}
</div>
<br><br>
{% endblock %}

after doing this, I have "Error during template rendering"

In template F:\django\mysite_1\blog\templates\blog\post.html, error at line 8

Invalid filter: 'markdown'

[Baker]

Hey @Secretcat,

The only time I experience this is when I am not loading the Markdown Deux tags,

{% load markdown_deux_tags %}

Can you post your header.html contents?