#mail-send 3 articles

• "0 sent" hides whether anyone was even asked — boolean mail wrappers conflate refusal with an empty audiencegotchas / graphThe recipient side of the same trap: a denied group read becomes an empty audience, an empty audience becomes a benign false, and an approval queue notifies nobody
• /me/sendMail from an account without a mailbox can time out with 504 – and the Graph SDK retries it three more timesgotchas / graphNo MailboxNotEnabled error, just a 504 after ~30 s; the SDK RetryHandler repeats the non-idempotent POST up to 3×, so the button hangs ~2 min and a late success can send duplicates; check assignedPlans for an enabled…
• ApplicationAccessPolicy won't scope to a shared mailbox — use a mail-enabled security groupgotchas / graph"not a security principal"; scope app-only Mail.Send to a mail-enabled security group