Business email not working?

1. Check your mailbox in a browser

1. Open Outlook on the web through your usual Microsoft 365 sign-in. Avoid links in unexpected emails.
2. Check whether you can sign in and whether the missing message appears. Look in Junk, Deleted Items and both Focused and Other views if enabled.
3. Send a test message to a known colleague and ask for a reply. Record the time and any delivery error.

If webmail works but the app does not, focus on that device. If webmail also fails, recreating the desktop profile is unlikely to fix the underlying mailbox or service issue.

2. If only the Outlook app is affected

1. Confirm other websites load and read the connection or sign-in message shown in Outlook.
2. Close and reopen Outlook, then complete any legitimate sign-in prompt. Never approve an MFA request you did not initiate.
3. In classic Outlook for Windows, check that Work Offline is not enabled. This control does not apply to every Outlook version.
4. Install available Office updates. Tell support whether you use classic Outlook, new Outlook or Outlook for Mac.

Do not delete a profile or local mail file as a first step. POP accounts and local archives can contain messages that are not on the server.

3. If messages are missing in webmail too

Check mailbox storage and review inbox rules, forwarding and blocked senders. Ask the sender for the exact delivery error rather than assuming the message was sent successfully. Unexpected forwarding or rules should be treated as a possible security incident.

Your Microsoft 365 administrator can check service health, message trace, quarantine and mail routing. If several users are affected, report that immediately. DNS and connector changes should be made by someone who understands your existing mail setup.

What to send Bluewall

Include the affected address, the device and Outlook version, whether webmail works, the sender and recipient, the approximate message time and the complete error. Do not send passwords or MFA codes.

Get business email support · Concerned your account has been compromised?

Further guidance

Microsoft: sending and receiving problems in Outlook