Form.validate_on_submit() Doesn't Work(nothing Happen When I Submit A Form)

I'm creating a posting blog function for social media website and I'm stuck on a problem: when I click on the 'Post' button(on create_post.html), nothing happens. In my blog_posts/

Solution 1:

I solved the bug!!!!!!!! {{form.problem_submit.label(class="btn btn-secondary")}} should had been {{form.problem_submit(class="btn btn-secondary")}}