0x800CCC0F

Fix Outlook error 0x800CCC0F when sending emails

Software – Microsoft Office Intermediate 👁 0 views 📅 May 25, 2026

Outlook error 0x800CCC0F usually means your internet connection or mail server timed out while sending. The fix is almost always in your account settings or a corrupted send/receive profile.

Quick answer: Run Outlook as administrator once, then go to File > Account Settings > Account Settings > double-click your account > More Settings > Outgoing Server tab – check 'My outgoing server (SMTP) requires authentication'. Also under Advanced tab, set outgoing server (SMTP) port to 587 and encryption to TLS. Apply and restart Outlook.

I've seen error 0x800CCC0F hit hundreds of users – mostly Outlook 2016, 2019, and Microsoft 365. The error means Outlook tried to connect to your outgoing mail server (SMTP) but the connection timed out or got cut. The culprit here is almost always one of three things: your SMTP port or encryption is wrong, your antivirus is scanning and blocking outgoing email, or your Outlook profile is corrupted. Let's walk through the fixes in order.

1. Check your SMTP settings

Most people pick 'Autodiscover' and assume Outlook configures everything right. It doesn't always. Start here:

  1. Open Outlook.
  2. Go to File > Account Settings > Account Settings.
  3. Select your email account and click Change.
  4. Click More Settings.
  5. Go to the Outgoing Server tab.
  6. Check My outgoing server (SMTP) requires authentication then select Use same settings as my incoming mail server.
  7. Go to the Advanced tab.
  8. For Outgoing server (SMTP), set Port to 587 and Encryption to TLS. Some providers use port 465 with SSL – check your provider's docs.
  9. Click OK and then Next, then Finish. Restart Outlook and try sending.

2. Disable antivirus email scanning (temporarily)

Most antivirus tools (Norton, McAfee, even Windows Defender sometimes) have an 'email scanning' feature. It intercepts SMTP traffic and can cause timeouts. Disable it long enough to test:

  1. Open your antivirus software.
  2. Look for settings related to email scanning, outgoing email, or SMTP protection.
  3. Disable that feature (or pause protection entirely).
  4. Try sending a test email from Outlook.
  5. If it works, re-enable everything and add an exception for Outlook or the SMTP port (587 or 465).

3. Run Outlook in Safe Mode and disable COM add-ins

Third-party add-ins can intercept SMTP and cause hangs. Test this:

  1. Hold Ctrl and double-click the Outlook shortcut. Confirm Safe Mode when prompted.
  2. Try sending an email. If it works, close Outlook and restart normally.
  3. Go to File > Options > Add-ins.
  4. At the bottom, next to 'Manage', select COM Add-ins and click Go.
  5. Uncheck all add-ins except maybe 'Microsoft Exchange' if you use it.
  6. Click OK and restart Outlook. Then re-enable add-ins one by one until you find the culprit.

4. Repair your Outlook data file (.pst or .ost)

If the above don't work, the data file might be corrupt. The error 0x800CCC0F can also appear if the outgoing queue (your Outbox) is stuck on a corrupted message.

  1. Close Outlook.
  2. Find SCANPST.EXE. Its location depends on your Office version – for Office 365 it's usually C:\Program Files\Microsoft Office\root\Office16\SCANPST.EXE. For older versions, check C:\Program Files (x86)\Microsoft Office\OfficeXX\SCANPST.EXE.
  3. Browse to your PST file. Default path: C:\Users\[YourUsername]\AppData\Local\Microsoft\Outlook.
  4. Run SCANPST on that file. Let it repair any errors.
  5. Open Outlook and try sending.

5. Create a new Outlook profile

This is the nuclear option, but it fixes the issue 90% of the time when nothing else does.

  1. Close Outlook.
  2. Go to Control Panel > Mail (32-bit). If you can't find it, search for 'Mail' in Control Panel.
  3. Click Show Profiles.
  4. Click Add, give it a name like 'NewProfile', and set up your email account.
  5. Under 'When starting Microsoft Outlook, use this profile', select Prompt for a profile to be used or set the new one as default.
  6. Close the dialog and open Outlook. Choose the new profile. If everything works, you can delete the old profile later.

Alternative fixes (if the main ones fail)

  • Check your internet connection – run ping smtp.gmail.com (or your provider's SMTP server) from Command Prompt. If you get timeouts, it's a network or firewall issue.
  • Disable IPv6 on your network adapter – some routers cause SMTP timeouts over IPv6. Go to Network Connections, right-click your adapter, Properties, uncheck 'Internet Protocol Version 6 (TCP/IPv6)'. Reboot and test.
  • Check Windows Firewall – make sure Outlook.exe is allowed through the firewall for outbound connections on ports 587 or 465.

Prevention tip

Once you fix it, stop it from coming back. Keep your antivirus email scanning disabled (it's redundant anyway – modern email providers scan on their end). Stick with SMTP port 587 and TLS – it's the most universally supported. Also, regularly run SCANPST on your PST file every few months, especially if you get frequent send/receive errors. One corrupted email in your Outbox can trigger 0x800CCC0F repeatedly – so clear your Outbox manually every week if you send a lot of attachments.

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