Outlook Not Sending or Receiving Emails

Applies to: Outlook for Windows, Outlook for Mac, Outlook.com desktop app

If Outlook's stuck showing "Sending..." forever, mail's piling up in the Outbox, or nothing new is arriving — work through these in order. Most people I talk to are fixed by step 3.

1. Check Outlook's connection status

1. Look at the bottom status bar (Windows) or the top of the window (Mac) for "Working Offline" or "Disconnected."
2. Says Working Offline? Send/Receive tab → click Work Offline to toggle it back on.

2. Send/Receive manually

1. Press Ctrl+Alt+S (Windows) or go to Send/Receive → Send/Receive All Folders.
2. Watch for an error dialog — note the exact error code if one shows up, it'll matter later.

If you're syncing a Gmail or Yahoo account specifically and see error 0x800CCC0E or 0x800CCC0F, that's a documented, known issue with classic Outlook's syncing of those accounts — Microsoft has an official support article with the current workaround, so search that exact error code rather than guessing at general fixes.

3. Mail seems to have stopped arriving, but nothing's actually broken

Before assuming anything's wrong, check whether Focused Inbox is on (View tab → Show Focused Inbox). It splits your inbox into "Focused" and "Other," and mail that Outlook decides isn't a priority lands in the tab you're not looking at — this gets mistaken for "not receiving" constantly. Turn it off if you'd rather see everything in one list.

4. Clear a stuck Outbox item

A single corrupted message — usually one with a large attachment — can block the entire queue behind it. I see this constantly.

1. Open the Outbox folder.
2. Open the oldest stuck message.
3. Remove any large attachment, or delete and rewrite the message.
4. Send again.

If that doesn't shake it loose, try this instead: right-click the stuck message → Move → Other Folder → Drafts, then open it from Drafts and hit Send from there. Moving it out of the Outbox and back in sometimes clears whatever got it stuck in the first place, without you needing to touch any settings.

Worth knowing the actual limit while you're in here: most personal accounts (Gmail, Outlook.com-style) cap attachments around 20MB total; Exchange accounts are usually capped closer to 10MB. If you're near that, split the files across separate emails or send a cloud storage link instead.

5. Double-check the recipient address

Obvious once you think to check it, easy to miss when you're troubleshooting settings instead — a typo in the "To" field will make a message sit and fail just like a server problem would. Clear the field and retype the address rather than trusting what's already there.

6. Recheck your account settings

1. File → Account Settings → Account Settings.
2. Double-click your account, click More Settings → Outgoing Server, and confirm "My outgoing server (SMTP) requires authentication" is checked.
3. Under Advanced, confirm the port numbers match your provider's current requirements — most now want SSL/TLS on port 587 or 465.

7. Repair your Outlook profile

1. Windows: Control Panel → Mail → Show Profiles → select your profile → Properties → Email Accounts → select account → Repair.
2. Mac: Outlook → Preferences → Accounts → remove the account, restart Outlook, then re-add it.

8. Repair the Office installation itself

This is different from step 7 — a profile repair fixes a broken connection between Outlook and your account; this fixes Outlook's own core files if they've become corrupted, which shows up as the same symptoms but needs a different tool.

1. Control Panel → Programs → Uninstall a program.
2. Select your Microsoft Office installation → Change (near the top).
3. Choose Quick Repair first and let it run.
4. Still stuck afterward? Go back and choose Online Repair instead — it's slower but replaces more than Quick Repair does.

9. Try Safe Mode to rule out an add-in

If the problem is intermittent or started right after installing some add-in (an antivirus toolbar, a CRM plugin, anything like that), a corrupted or misbehaving add-in is worth ruling out before anything more drastic.

1. Press Windows key + R, type outlook.exe /safe, and press Enter.
2. Try sending a test email in Safe Mode.
3. If it works fine here, an add-in is the culprit — disable them one at a time under File → Options → Add-ins to find which one.

10. Still not working?

If none of this fixes it, the issue is usually on the mail server side — an expired password, an MFA prompt, or a provider outage. Try logging into that same account's webmail in a browser. If that also fails, it was never really about Outlook.