If you don't see your displays, it's normal to question whether they are working. To quickly answer this question, try the following:
Check for a timestamp. Select the display from the Convert dashboard and check for a Last viewed timestamp at the top-right. If the display is firing correctly and appearing to visitors, this timestamp will appear along with an increase in the display's performance metrics.
Use private browsing. While testing your displays, test in a different browser from the one you typically use to view your website. Almost all browsers have a setting that is commonly referred to as either Private browsing or Incognito mode. Viewing your site through this mode allows you to see it as if you're a first-time visitor and avoid various cookie/targeting-based suppression rules. Not sure how to access this setting? No problem. Here are a few links that provide you with steps on how to enable this setting in common browsers:
Note: This option allows you to trigger the display regardless of previous submissions, views, or dismissals and is the preferred troubleshooting option.