Bug fix for Python Bcrypt Password Hash working on Postgres Heroku

I have a Flask app. My code registers user supplied password in Postgress database on Heroku using bcrypt.generate_password_hash(password).decode('utf8'). However when the user logs back in, the login password don't not match with the password retrieved. I use bcrypt.check_password_hash(user.password.encode(), bytes(login_password, 'utf8')) to match. I need just fix for this, that I will try on my end.