This issue may occur if an entity that is not enabled to be an email recipient is defined in a One-Click-Action (OCA) as a “To”, “BCC”, or “CC” recipient.
In this example, the problematic record is an invoice record. To fix the issue, the user should edit the corresponding OCA to remove or replace the record.
If the issue persists, the user should contact our support team (support@mscrm-addons.com).

