Outlook shows email sent but not received

Question

I have a premium account and tried sending an email to myself, bcc to myself and 300 recipients.

The email shows up in the sent folder but i have not received the email bcc to myself and have not heard from any of my 300 recipients.

What does this mean? Was my email sent to my 300 recipients?

Answer 1

Did you check your Junk Email and Deleted Items folders for the Bcc copy?

If there are no delivery failure messages and you sent to 300 recipients in one email, the message was accepted into Sent but not fully delivered due to sending limits.

Answer 2

Did you receive any delivery failure or delay messages in your Inbox or Junk folder?

Answer 3

Hello, how many emails have you sent today before this message?

Outlook.com has built in sending limits to reduce spam. You are allowed up to 100 recipients per message and about 500 recipients per day. If you exceed this, messages still appear in Sent but delivery gets blocked or delayed. To fix this, split your list into smaller groups under 100 recipients, wait between sends, and check Sent Items for any delivery status notifications. This helps ensure messages are accepted and delivered properly.

Answer 4

What is the limit number of recipients in each batch that I can send to?

Answer 5

In Outlook.com, an email appearing in the Sent folder means Outlook successfully handed the message to the outgoing mail server. It does not guarantee that the message was delivered to all 300 recipients or to the Bcc copy on the same account.

For large recipient lists and Bcc to self, several things can happen:

1. Message may be blocked or treated as spam
   • A message with 300 recipients can trigger spam or bulk-mail filters, either on Outlook.com’s side or on recipients’ servers.
   • The copy to the same Outlook.com account (Bcc to self) may be filtered to Junk Email or blocked by rules.
2. Sending limits or throttling
   • Outlook.com enforces sending limits, especially for new or low‑reputation accounts. If a limit is hit, some or all recipients may not receive the message even though it appears in Sent.
   • In such cases, a non‑delivery report (NDR) is often generated, but not always for every blocked recipient.
3. Recipient‑side issues
   • Individual recipients may have full mailboxes, invalid addresses, or spam filters that silently drop the message.
   • If any addresses are invalid or blocked, Outlook.com typically returns an NDR explaining the reason.
4. Check whether the Bcc copy to self was received
   On the Outlook.com account that sent the message:
   • Check Junk Email and any custom folders.
   • Review rules and blocked senders:
     • Sign in to Outlook.com.
     • Go to Settings > Mail/Options > Blocked Senders or Block and allow and confirm the sender address or domain is not blocked.
5. What this means for the 300 recipients
   • The fact that the message is in Sent means Outlook.com attempted to send it.
   • It does not confirm that all 300 recipients actually received it.
   • To verify, look for any NDRs in the Inbox or Junk Email folder. Those will indicate addresses or domains where delivery failed.

If no NDRs appear and the Bcc copy to self is not in Inbox or Junk, the message may have been filtered or blocked as bulk mail. For future large mailings, consider:

• Sending to smaller batches.
• Using a distribution list or a proper bulk‑mail/marketing service that handles large recipient lists and delivery reporting.

---

References:

• Can't send or receive email in Outlook.com
• Where are my email messages or calendar events in Mail and Calendar for Windows 10?