You may see this Facebook Lead Ads error in a Zap run history or when testing the New Lead trigger: "CRM access has been revoked from Lead Access Manager".
Zapier doesn’t have CRM access in your Facebook Lead Ads account. CRM access may have been removed or revoked by an account admin.
To grant Zapier CRM access, follow Facebook's instructions on granting lead access permission to a CRM system.
Once that's done, reconnect your Facebook Lead Ads account in Zapier: