Error Code 0x800CCC0E

Question

Error Code 0x800CCC0E

Marilyn Hood 0

Unable to connect to server. Error code 0x800CCC0E

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2 answers

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Answer 1

Clary-N 16,565 Microsoft External Staff Moderator

Hi Marilyn Hood,

Thanks for sharing the error details. To narrow this down, could you confirm which email provider you’re using, which version of Outlook you have and whether the problem affects sending, receiving or both? Also, can you access the account and send or receive messages normally through webmail?

If webmail works, make sure Work Offline isn’t enabled in Outlook, then install any available Office updates and try repairing the account under File > Account Settings > Account Settings > Email > Repair. If Repair isn’t available or the error continues, please let me know what happens when you test on another network, such as a mobile hotspot. This can help determine whether the connection is being blocked by the current network, VPN, firewall or security software.

Please let me know what happens after these checks and I’ll help you narrow down the next step.

Clary-N 16,565 Reputation points Microsoft External Staff Moderator

2026-10-02T08:45:55.02+00:00

Hi Marilyn Hood,

May I know if you have got any chance to check my answer?

I am glad to help if you have any other questions.
Marilyn Hood 0 Reputation points

2026-10-02T16:11:33.1+00:00

Thank you for your reply. I have two outlook email addresses, one is personal and no issues with the VPN and the ISP; the other is a business email using a different server and that's the one with the issues. I've done all the troubleshooting through mulitple sources, checked all settings but I have to turn off the Avast Secureline VPN for the email to work and receive messages. It happens on my desktop only, my laptop is fine. I am not at all skilled in this sort of thing and because I am a subscriber to Microsoft I was hoping they could take over the computer as they have done in the past to diagnose and fix the issue - apparently this service is no longer available. I spent nearly five hours trying to find a fix and it's too time consuming and like I said, I lack the skills ( and confidence) to figure this out. I will just continue to turn off the VPN when using my desktop. Thank you!!
Clary-N 16,565 Reputation points Microsoft External Staff Moderator

2026-10-06T06:43:18.7233333+00:00

Hi Marilyn Hood,

Thank you for the detailed update. Since the business account works on your laptop and on the desktop as soon as Avast SecureLine VPN is disconnected, this does appear to be specific to how the VPN is handling that business mail server on the desktop.

I completely understand why you don’t want to spend any more time troubleshooting this yourself after already putting nearly five hours into it. If turning off the VPN temporarily is the most practical option, just remember to reconnect it afterward. You could also contact Avast support and ask whether they can help allow the business mail server through SecureLine without requiring you to disable the VPN.

Thank you again for explaining what you found and I hope they can help you get this resolved without more trial and error.

Best regards.

Answer 2

Error 0x800CCC0E in Outlook means Outlook cannot connect to the mail server.

For this error, use these checks and fixes:

If the account is Gmail or Yahoo in classic Outlook
- A known issue affected Gmail and Yahoo accounts and could also happen after a password change.
- Close Outlook.
- Open Credential Manager from the Windows Start menu.
- Go to Manage your credentials > Windows Credentials.
- Under Generic credentials, find entries that start with MicrosoftOffice16_Data:OAUTH2 and remove the relevant ones.
- Reopen Outlook and sign in again when prompted.
- After a password change, Outlook may not prompt immediately; it can take about one hour for the OAuth token to expire.
If the account uses IMAP or POP and the connection was interrupted
- The issue can be caused by an invalid App Password.
- Sign in to the email provider’s webmail, go to Account Information > Security, and create a new App Password.
- In Outlook, go to File > Account Information > select the affected IMAP account > Account Settings > Server Settings.
- Paste the new App Password into the Password box, then select Next and Done.
Check for third-party add-ins
- Start Outlook in safe mode: Start > Run > type outlook.exe /safe > OK.
- If Outlook works in safe mode, disable third-party COM add-ins:
  - File > Options > Add-Ins
  - In Manage, select COM Add-ins > Go
  - Clear the check boxes for third-party add-ins
  - Restart Outlook
Windows 10 only: TLS 1.3 workaround for IMAP/POP interruptions
- This is a registry change and should be done carefully.
- Open Regedit and go to: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols
- If TLS 1.3 exists under Protocols, first export the key as a backup.
- Delete the TLS 1.3 key and its subkeys.
- Restart Outlook. If mail still does not sync, restart Windows.

If the error is specifically with Gmail or Yahoo, the Credential Manager fix is the primary workaround.