E-mails stuck in the Outlook Outbox: why they do not leave and how to send them

E-mail·· 10 views· 3 min read

The short answer: a message that stays in the Outbox (in italics, or with a number beside it) is one Outlook has not managed to hand to the server yet. The usual causes are the outgoing server (port, security or authentication), a large attachment, offline mode, or the message itself getting stuck because it was opened while waiting.

Why it gets stuck

Symptom Most likely cause
They all get stuck, and receiving works The outgoing server is wrong: “My outgoing server requires authentication” is off, or the network blocks port 465 (use 587 with STARTTLS).
Only one gets stuck Almost always a large attachment, bigger than the server accepts, or a message you opened while it was in the Outbox, which marked it as “do not send”.
They get stuck and 0x80042109 or 0x800CCC0E appears Outlook cannot reach the outgoing server. See common Outlook errors.
They leave but come back in an error message This is no longer Outlook: the message reached the server and was refused further on (wrong address, recipient’s mailbox full). Read the bounce, it says why.
Nothing goes out or comes in Outlook is offline: getting back online.

Getting them out

1 Make sure you are online and press Send/Receive All Folders (F9).
2 If it is a single message: switch Outlook to Work Offline, drag that message from the Outbox to Drafts, go back online, open the draft and send it again.
3 If it has a large attachment, remove it and send the file another way (a sharing link, for example). Try sending the same message without the attachment to confirm.
4 If they all get stuck, open File > Account Settings > Change > More Settings: on the outgoing server tab tick “My outgoing server (SMTP) requires authentication” using the same settings as incoming; on the Advanced tab confirm port 465 with SSL/TLS, or 587 with STARTTLS.
5 Test on another network (your phone’s data). If it goes out that way, the network is blocking sending.
6 Send yourself a test message without an attachment. If it arrives, the problem was the message, not the account.
Do not open the message while it sits in the Outbox. Opening and closing it without sending makes Outlook stop trying. Drag it to Drafts and send it from there.
To send large files a sharing link is usually better than an attachment: it fills nobody’s mailbox and never gets stuck.

Messages still stuck? Tell us your address and the error code, if one appears.

Open a support ticket

SEE ALSO

Common Outlook errors: 0x800CCC0E, password prompts and more

Outlook shows Disconnected or Working Offline: how to get it back online

Outlook is not syncing: missing e-mails and folders that do not update

Your mailbox is full: what to delete and how to stop it happening

How to access your webmail

How to set up your e-mail in Outlook 2016 and 2019

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