Не срабатывает db.session.commit() на Flask

from flask import Flask, render_template, url_for, request, redirect, flash, session
from flask_sqlalchemy import SQLAlchemy
import datetime
from flask_login import LoginManager, UserMixin, login_user, login_required, logout_user, current_user
from werkzeug.security import check_password_hash, generate_password_hash
 
 
app = Flask(__name__)
app.secret_key = 'zondercraftwarzeig'
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)
manager = LoginManager(app)
 
 
class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    login = db.Column(db.String(30), nullable=False, unique=True)
    password = db.Column(db.String(255), nullable=False)
 
    def __repr__(self):
        return f'<{self.login}:{self.id}>'
 
 
class Article(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=False)
    intro = db.Column(db.String(300), nullable=False)
    text = db.Column(db.Text, nullable=False)
    date = db.Column(db.DateTime, default=datetime.datetime.utcnow)
    author = db.Column(db.String(30))
 
    def __repr__(self):
        return f'<Article {self.id}>'
 
 
@manager.user_loader
def load_user(user_id):
    return User.query.get(int(user_id))
 
 
@app.route('/')
@app.route('/home')
def index():
    return render_template('articles.html')
 
 
@app.route('/login', methods=['GET', 'POST'])
def login_page():
    login = request.form.get('login')
    password = request.form.get('password')
    if request.method == 'POST':
        if login and password:
            user = User.query.filter_by(login=login).first()
            if user and check_password_hash(user.password, password):
                login_user(user)
                next_page = request.args.get('next')
                return redirect(url_for('user_page'))
            else:
                flash('Неверное имя пользователя или пароль')
        else:
            flash('Пожалуйста, заполните все поля')
    return render_template('login.html')
 
 
@app.route('/register', methods=['GET', 'POST'])
def register():
    login = request.form.get('login')
    password = request.form.get('password')
    password2 = request.form.get('password2')
    if request.method == 'POST':
        if not (login or password or password2):
            flash('Пожалуйста, заполните все поля')
        elif password != password2:
            flash('Пароли разные')
        else:
            hash_password = generate_password_hash(password)
            print('hash is ready')
            new_user = User(login=login, password=hash_password)
            print('new_user created')
            db.session.add(new_user)
            db.session.commit()
            print('User created successfully')
            return redirect(url_for('login_page'))
 
    return render_template('register.html')
 
 
@app.route('/logout', methods=['GET', 'POST'])
@login_required
def logout():
    logout_user()
    print('user вышел')
    return redirect('/')
 
 
@app.after_request
def redirect_to_signin(response):
    if response.status_code == 401:
        return redirect(url_for('login_page') + '?next=' + request.url)
    return response
 
 
@app.route('/about')
def contacts():
    return render_template('contacts.html')
 
 
@app.route('/articles')
def articles():
    arts = Article.query.order_by(Article.date.desc()).all()
    return render_template('articles.html', arts=arts)
 
 
@app.route('/articles/<int:id>')
def article_detail(id):
    art = Article.query.get(id)
    return render_template('article_detail.html', art=art)
 
 
@app.route('/articles/<int:id>/delete')
@login_required
def article_delete(id):
    art = Article.query.get_or_404(id)
    try:
        db.session.delete(art)
        db.session.commit()
        return redirect('/articles')
    except:
        return 'При удалении статьи произошла ошибка'
 
 
@app.route('/user_page', methods=['POST', 'GET'])
@login_required
def user_page():
    user = current_user.login
    my_articles = Article.query.filter(Article.author == user).all()
    return render_template('user_page.html', my_articles=my_articles)
 
 
@app.route('/create_article', methods=['POST', 'GET'])
@login_required
def create_article():
    if request.method == 'POST':
        title = request.form['title']
        intro = request.form['intro']
        text = request.form['text']
        date = datetime.datetime.utcnow
        article = Article(title=title, intro=intro, text=text, date=date, author=current_user.login)
        try:
            db.session.add(article)
            print('Article added')
            db.session.commit()
            print('Article commited')
            return redirect('/articles')
        except:
            return "При добавлении произошла ошибка"
    else:
        return render_template('create_article.html')