You may get SMTP Error as An unknown error has occurred Outlook Mail SMTP Error 0x800CCC67 in Microsoft Outlook or Windows Live Mail. Usually it occurs when you try to send an email from Microsoft Outlook or Windows Live Mail. As we observed most common reason for this issue would be changes or updates in SSL or Port settings. And Anti-Virus or Firewall blocking SMTP access.
RECOMMENDED: Fix this issue in 3 simple steps. Takes only 2 minutes.
1) Download repair utility.
2) Install program and click Scan button.
3) Click Fix Errors button when scan is completed.
4) Restart your computer.
This issue may occur if one of the following scenarios is true:
- Your Outlook might be disconnected or not connected to Internet.
- Incorrect settings of Outlook mail account.
- Incomplete installation of Outlook
- Incorrect configuration of Antivirus software
- When your Outlook user profile is damaged.
- If Outlook email item on your POP3 server is damaged.
- When Outlook is removed or installation of Outlook is damaged.
When you attempt to send or receive email, you see one of the following error messages.
- An unknown error has occurred. Subject ”, Account: ‘mail.isot.com’,
Server: ‘mail.isot.com’, Protocol: SMTP, Server Response: ‘421 mail.isot.com
connection refused from [220.127.116.11]’, Port: 25, Secure(SSL): No, Server
Error: 421, Error Number: 0x800CCC67
An unknown error has occurred Outlook Mail SMTP Error 0x800CCC67
To resolve this issue, use one or more of the following methods. After you complete each method, send yourself a test email message to make sure that you can send and receive messages without receiving an error message. If you continue to receive errors, try the next method.
Quick Note: Before making any changes in your computer, I suggest you to create a System Restore point so that you can restore back your computer to previous working stat if something goes wron.
Step 1: Make sure that you are connected to the Internet and able to telnet SMTP port number.
To do this, follow these steps:
- Start an Internet browser.Or ping the google.com; ping www.google.com. You should get reply as below if the computer connected with Internet.
- Type one of the following addresses in the address bar, and then press Enter.
- Check for the proxy settings as well.
Telnet’ing the SMTP port :
- Type command as telnet smtp.servername.com 25.
- Example: If you have a google domain account. The telnet command should be: telnet smtp.gmail.com 25.
- You will get the reply as below If not contact ISP (Internet Service Provider).
Step 2: Make sure that your Outlook email account settings are correct.
Incorrect email account settings can also cause the issues. We have listed some major Internet Service Providers settings (for manual configuration of Outlook)
We recommend that you contact your Internet service provider (ISP) for information about the exact incoming and outgoing mail server names and settings that you should use when you configure your Internet email account in Outlook. The list provided here contains information only for some Internet service providers in the United States and may not be up to date.
Incoming Mail (POP3) server names and settings:
|Provider Name||Server Name||Port||SPA||SSL||AuthRequird|
|Qwest||pop.[enter state ID].qwest.net||110||OFF||OFF||OFF|
Outgoing Mail (SMTP) server names and settings:
|Provider Name||Server Name||Port||SPA||AuthRequired||Encryption|
|Qwest||pop.[enter state ID].qwest.net||25||OFF||OFF||None|
Step 3: Disable or uninstall anti-virus.
Check your antivirus manufacturer’s website for additional suggestions or Disable the antivirus software. And Disable the firewall in router. If you found outlook is working fine after disable the antivirus software, highly recommended to uninstall the same using their removal tool and reinstall it.
Follow below links to disable, uninstall or reinstall antivirus software from your computer
- How to temporarily disable any antivirus firewall
- Remove-reinstall Norton anti-virus using Norton removal tool
- Completely uninstall AVG products
- Disable Windows Defender in Windows 8/10
- Turn Windows Defender on or off in Windows 8
- Turn Windows Defender on or off in Windows 7
List of manual antivirus uninstallers:
Click the link associated with the antivirus software currently installed on your system and follow the prompts or instructions on the website. After uninstall, reboot the computer.
- CA Antivirus
- Comodo Internet Security
- Cyber Defender Early Detection Center
- Dr. Web : (Only registered Dr.Web users can access support content)
- FRISK F-PROT Antivirus for Windows
- G Data
- K7 Total Security
- Microsoft Security Essentials
- Norman Virus Control/Norman Security Suite
- Norton (Symantec)
- Norton Security Scan
- Panda Cloud Internet Protection
- Pareto Logic
- Spybot Search & Destroy
- Total Defense Anti-Virus (formerly CA Anti-Virus)
- Trend Micro
- Trend Micro Titanium
- Trend Micro Worry-Free Business Security Agent
- Vipre (Sunbelt Software)
- Windows Defender
- Windows Live OneCare
- Windows Security Essentials
- Zone Alarm
Step 4: Create New Outlook Profile and Reconfigure email client.
- Go to Control panel, Click on Mail Option.
- Click Show Profiles
- Click Add
- Type a name for your profile.
- Outlook 2007 and above versions support “AutoDiscovery“. This will set up your email account automatically. Enter your name, email address and password and Outlook will try to set up the profile. If it does not work, proceed with “Manually configure server settings or additional server types” and continue.
Refer below links to create Outlook Profile and Mail Configuration.
- Create Microsoft Outlook Profile and Mail Configuration
- Add Mail Account in Windows Mail and Calendar App
Hope above resolutions steps helped you to fix the An unknown error has occurred Outlook Mail SMTP Error 0x800CCC67 issues. If not you need to contact your email providers or Internet service provider. Meanwhile ask your queries in comments or Forum.