Ошибка 401 при запуске flask-приложения

Пытаюсь вывести форму авторизации при запуске приложения, возвращается ошибка 401. Прошу помочь с данной проблемой.

conn = psycopg2.connect(dbname=DB_NAME, user=DB_USER, password=DB_PASS, host=DB_HOST)
login_manager = LoginManager()
login_manager.init_app(app)

@login_manager.user_loader
def load_user(user_id):
   return get(user_id)

class User(UserMixin):
   def __init__(self, username, password):
       self.id = username
       self.password = password
@staticmethod
def get(username):
   cur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)
   cur.execute("SELECT id, username, password FROM users WHERE username = %s", (username,))
   user_data = cur.fetchone()

   if user_data:
      return User(id=user_data[0], username=user_data[1], password=user_data[2])
   else:
      return None

 @app.route('/register', methods=['GET', 'POST'])
 def register():
    form = RegistrationForm()
    if form.validate_on_submit():
       cur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)

       hashed_password = generate_password_hash(form.password.data, method='pbkdf2:sha256')

       cur.execute("INSERT INTO users (username, password) VALUES (%s, %s)", (form.username.data, hashed_password))
       conn.commit()

       flash('Registration successful! You can now log in.', 'success')
       return redirect(url_for('login'))
   return render_template('register.html', title='Register', form=form)

 @app.route('/login', methods=['GET', 'POST'])
 def login():
    form = LoginForm()
    if form.validate_on_submit():
       user = get(form.username.data)

    if user and check_password_hash(user.password, form.password.data):
        login_user(user)
        flash('Login successful!', 'success')
        return redirect(url_for('FO'))
    else:
        flash('Login unsuccessful. Please check your username and password.', 'danger')

    return render_template('login.html', title='Login', form=form)

 @app.route('/')
 @login_required
 def FO():
    cur = conn.cursor(cursor_factory=psycopg2.extras.DictCursor)
    s = "SELECT * FROM public.fo"
    cur.execute(s)
    fo = cur.fetchall()
    return render_template('fo.html', fo = fo)