By default, flows have a 24-hour lifetime. This means that if a user does not interact with a question, menu, or template step within 24 hours, the flow automatically expires and the user is removed from it. Any responses received after the 24-hour period are ignored.
You can change this behavior by setting a timeout for these steps. To do so, go to a step in your Flow where you are waiting for a user's response.
In the step's settings, enable the option: "Go to another step if the user doesn't answer within a certain period of time." This will create a new "No Answer" branch in the flow that will be executed if the user does not respond within the specified time. If left empty, the flow will expire after the specified time.
Note that if you adjust the time to more than 24 hours, the next action in your flow must be a template message. This is due to WhatsApp’s 24-hour conversation window.