Airflow Dag won't move past "queued" state

This code was working just fine a couple hours ago, but suddenly my dags started getting stuck in "queued" state.

Here's what I'm trying to run:

from airflow import DAG
from airflow.operators.python_operator import PythonOperator
from datetime import datetime as dt

def test_function():
    print('Hello there')

default_args = {
    'owner': 'airflow',
    'depends_on_past': False,
    'email_on_failure': False,
    'email_on_retry': False,
    'retries': 0
}

with DAG(
    'test',
    default_args=default_args,
    description='A dag used for testing...',
    start_date=dt(2017, 1, 1),
    tags=['example']
) as dag:

    start = PythonOperator(
        task_id='test',
        python_callable=test_function,
        dag=dag
    )

    start

Here's what it looks like when it gets stuck.

If I replace the PythonOperator with a PostgresOperator it gets stuck as well.

The DummyOperator runs just fine.

source https://stackoverflow.com/questions/72368986/airflow-dag-wont-move-past-queued-state