title: AWS RDS for PostgreSQL cannot be connected after several hours
body: <p>I created several instances of RDS with PostgreSQL and get the same problems:</p>
  
  <ul>
  <li>I can connect to all of them right after creating the instances.</li>
  <li>After several hours (I stop working on it, turn off my laptop), I cannot connect to any of them again.</li>
  <li>I use DBeaver for the connections, the error show is "Connection attempt timed out."</li>
  </ul>
  
  <p>I attached the information of the
  <img src="https://i.stack.imgur.com/hjlsa.png" alt="RDS instances">. Hope someone can help me with this problem. Thank you in advance.</p>