Present, if user login via sns failed, they will be redirected to `/`, we can provide an optional for user to customize the url. see https://github.com/python-cn/flask-social-blueprint/blob/develop/src/flask_social_blueprint/core.py#L77
Present, if user login via sns failed, they will be redirected to
/, we can provide an optional for user to customize the url.see https://github.com/python-cn/flask-social-blueprint/blob/develop/src/flask_social_blueprint/core.py#L77