Sending, receiving, and organizing email in Outlook.com
If the message is in Sent, it was sent from Outlook, but delivery can still fail or be filtered after that. Try these checks in order:
- Confirm the recipient address again Even a small typo, outdated address, or changed domain can prevent delivery.
- Check whether the recipient’s mailbox is full or unavailable If their mailbox is full, they may not receive new mail until they clear space.
- Wait and resend once Some errors are temporary, such as connection timeouts, remote server issues, or temporary resource problems.
- Reduce message size In Outlook.com, messages with attachments larger than 25 MB cannot be sent. If the message is large, upload the file to OneDrive and send a link instead.
- Remove the email signature and resend A signature can sometimes affect sending in Outlook.com.
- Try sending from Outlook.com in the browser If the message was sent from Outlook or another email app, try sending the same message directly from Outlook.com.
- Ask the recipient to check spam, quarantine, or mail filtering on their side If there is no delivery failure message and the address is correct, the message may be blocked, quarantined, redirected, or treated as spam by the recipient’s mail system. If the recipient uses a work or school account, their IT administrator can check message trace and mail flow filtering.
- If only some recipients in a group do not receive it Review the addresses shown in the error report and remove old or invalid addresses from the group.
- If Outlook.com shows a non-delivery receipt even though the address is correct Use Sender Support in Outlook.com.
If the issue happens only with one specific recipient or organization, the most likely cause is filtering or blocking on the recipient side.
- Sent email in Outlook.com comes back "delivery failed"
- Can't send or receive email in Outlook.com
- My messages always show as sent, but the recipient doesn't receive them. This seriously hinders the already poor communication efficiency. Could you please help me figure out what the reason is? Thank you! - Microsoft Q&A
- Sent email in Outlook.com comes back "delivery failed"
- Sent email in Outlook.com comes back "delivery failed"