Understanding Facebook Ads Manager

I launched a campaign yesterday to convert to a free video course. The campaign has been set up using a Mailmunch landing page to capture email addresses which then transfers the details to mailerlite which then sends out the video course.

I have used pixel tracking on the Mailmunch thank you page (the page that shows AFTER the person has provided their details). Facebook Ads is telling me on the 'Results' Column that 210 have seen this, but I have only had 63 subscribers addresses come through to mailmunch and subsequently mailerlite.

I have paused the campaign as need help understanding the figures as well as the other columns.