ISSUE: I have stopped receiving leads on my lead generation form I have setup.
There are cases where a user will only receive their leads the first time their integration is turned on, this just means that default permissions need to be restored for the Facebook account you are attempting to use.
SOLUTION: Restore default permissions in Facebook.
You can use the steps below to assist you in resetting your default permissions in Facebook:
If you've customized access to leads in Business Manager, you can remove those changes at anytime using Restore Default Access. If you choose to restore default access, Page Admins and partners with the Page Admin role will receive access to your leads and all other Page roles won't get access. Keep in mind that if you use this feature, any changes you've made to permissions in the past will be removed, and your settings will be restored to default.
Facebook has documentation on this here, You can use the steps below to assist you in resetting your default permissions in Facebook:
Go to your Business Manager Settings. Click Integrations in the left menu. Click Leads Access. Click Restore Default Access in the top right corner.
2. Click Restore Default Access in the top right corner. Click Restore Default.
Once this has been done, you can test to make sure your leads flow seamlessly with the lead ads testing tool here: https://developers.facebook.com/tools/lead-ads-testing/