login_endpoint.py

  
@app.route('/')
@app.route('/index', methods=['GET','POST'])
def index():
  form_login = LoginForm()    
    if form_login.validate_on_submit():
        user = User.query.filter_by(username=form_login.username.data).first()
        if user:
            login_user(user)
            flash('logged in successfully as {}.'.format(user.username))
            next_page = request.args.get('next')
            return redirect(next_page or url_for('index'))
        flash('Incorrect username or password', 'error')
    print("AQUI ESTA O PROBLEMA")
    return render_template('index.html', form=form_login)