Use this guide when a message stays in the Outbox, Outlook shows a connection problem, or recipients say that your message never arrived. First establish whether the issue affects one message, one device, or your whole mailbox.
Check the scope of the problem
- Confirm that your internet connection works and note any Outlook connection or sign-in message.
- Open your organization’s Outlook on the web using your usual trusted Microsoft 365 sign-in page. Send a short message without attachments to a colleague who can confirm receipt.
- If the web test works, the desktop application or original message may be the problem. If it also fails, record the error rather than repeatedly sending the same message.
Check the message and Outlook connection
In classic Outlook for Windows, check whether Work Offline is enabled on the Send/Receive tab. Turn it off if you intend to connect. Menus differ in new Outlook and Outlook on the web.
Review the recipient address and attachments. If one message is stuck, keep a copy of its text, remove large attachments, and retry once. Use your organization’s approved file-sharing method for large files. Avoid deleting an Outlook profile or local data files as an initial troubleshooting step.
What to include in your ticket
- Your mailbox address, device, and Outlook version.
- When the problem began and whether Outlook on the web works.
- The exact error, affected recipient domain, and attachment size.
- Whether you received a delivery-failure message; include its diagnostic text.
When to contact AvrinTech
Contact us when the web test also fails, several users are affected, or messages remain stuck after these checks. Identify any business deadline. Do not send your password or MFA code in the ticket.
Further guidance: Microsoft: Outlook messages stuck.
