FlaskApp has no attribute 'config'
There was a mistake here db.init_app(app). I changed it to db.init_app(application) and it is working success now.
Here is one way you can set up your Flask application with Connexion.
import connexion# This creates the connexion application instance.connexion_app = connexion.App(__name__)# This gets the underlying Flask app instance.flask_app = connexion_app.app # Flask(__name__)ðŸ¤