Part 1
Timestamps for Part 1:
00:30: Checking for signs of a broken connection
01:40: Check that the Facebook Form is mapped
03:20: Check the Workflow Trigger for Facebook Lead Form is correct
05:20: Checking the Connection with the Facebook Lead Ads Testing tool
07:00: How to Restore Leads Access from your Business Manager
If all of the above has not worked, please proceed to Part 2 below where you can reset the Lead Form connection my un-mapping and re-mapping the form.
After this, please test the form again at 5:20 in the first video above.
Part 2 - Resetting the Facebook From Mapping