[CONTEXT] Zapier is a freemium service that is able to "Connect your apps and automate workflows". A zap is already created in Zapier that enables you to create new leads coming from an infinite types of sources (e.g. ninjaform / facebook / google spreadsheet / etc.)
Connecting Zapier with an OdooSaas database is easy. Just follow the steps Zapier is giving you.
However - connecting Zapier with an Odoo.sh database is complexier.
It often gives you this error "Fault (code AccessDenied) occurred. Message: Access Denied"
Please check below answer to get this solved.