Automatic Deactivation of Inactive Ads in Meta Ads
Meta Ads will automatically deactivate ads that have not generated any results (i.e., the events we set) within the last 14 days.

Source: Meta Ads panel
What Does this Mean for You?
When this happens, you will receive a notification, and your ad will no longer be displayed. To resume its activity, you will need to create a new ad or edit the existing one, but in that case, it will be necessary to change its settings.