when I put a new DAG python script in the dags folder, I can view a new entry of DAG in the DAG UI but it was not enabled automatically. On top of that, it seems does not lo
This error can be misleading. If hitting refresh button or restarting airflow webserver doesn't fix this issue, check the DAG (python script) for errors.
Running airflow list_dags can display the DAG errors (in addition to listing out the dags) or even try running/testing your dag as a normal python script.
After fixing the error, this indicator should go away.