It would be useful if registered APIs could be granted permissions to send approval workflow emails. At present it is not possible for the API to send email regardless of config / permissions.

Our specific scenario is that we have a client with a pre-existing order portal, which , for which we created some middleware with an API registered in Entra. This has been granted permissions to send email via Microsoft Graph. Within BC, Permissions have been granted to API via Microsoft Entra Applications. Human approval is required via standard Sales Order Workflow with email notifications.

Process is that middleware API creates Sales Order in BC, then triggers approval process; hence is the approval sender. Notification is correctly created but emails always get stuck in Email Outbox with error 'You are not authorized to access this resource: https://graph.microsoft.com/.default. Contact your system administrator.' Infrequent approvers are unaware so order approval is delayed.

Please could a permission be created in either BC or Entra, allowing APIs to send workflow emails on the tenant. It currently appears that you have done so by granting permissions to send emails via Microsoft Graph in Entra, but this does not work for BC workflow emails.