Graph accepts the MIME message
smtpify365 uses `/me/sendMail`. Microsoft documents that this method returns 202 Accepted and saves to Sent Items by default. Acceptance does not prove final recipient delivery.
Dashboard counters
A counter increments after Graph accepts the request. smtpify365 currently stores a timestamp and connection ID, not recipient-level or bounce history.
Investigate downstream delivery
Use Microsoft 365 message trace and recipient-side checks when a submission succeeds but the message is absent.