First, make sure that:
Your website is published, and your Facebook page is public
You have added your pixel ID to your website's integrations settings
Make sure there are no multiple IDs: the pixel ID should be added only once, as adding a Facebook pixel twice could cause duplicate or incorrect data in reports
You have verified your domain for Facebook
(optional) You have added your website's domain to the allow list on Facebook pixel settings
Now, it's time to check it on your live website. You can use the Facebook Pixel Helper extension that shows if the integration is valid and what events are being tracked.
Follow this link and follow the on-screen instructions to add the Facebook Pixel Helper to your browser.
Access your website online.
Click on the extension to view the data; you will see both general data and event information:
NOTE: If you can't find the extension in the browser bar, click on the puzzle icon (the top right corner on Chrome) and pin your most-used extensions so that would be always visible and easily accessible: