How to Fix Outlook 0x800ccc0f Error

Error 0x800ccc0f “Your Server Has Unexpectedly Terminated the Connection” when you send an SMTP-based E-mail. This issue can raise seemingly ‘out of the blue’. When everything is going fine, the next Microsoft Outlook complains of issue 0×800ccc0f when trying to send an email.

It comes down to Microsoft products conflicting with Microsoft products, for instance, MS Window Firewall blocking MS Outlook. See if one of the cases below implies to you and follow the steps to fix the issue.

Why does 0x800ccc0f Outlook error occur?

This problem may occur if you have an antivirus e-mail protection utility enabled, which checks the mail as it comes in from your Post Office Protocol (POP) server this can usually happen when a server firewall blocks customer’s IP address or IP ranges based on the abnormal behavior. For example, some servers block access from IP address if the number of connection exceeds the limit, too many failed logins, simultaneous POP connections, etc. So, if the firewall blocks the user’s access, they will see Outlook reported error 0x800ccc0f.

Customer’s local firewall settings:-Likewise, a customer’s local firewall can sometimes block incoming and outgoing emails. That is, this issue can raise if the custom SMTP port is not added in firewall or if the priority of Microsoft Outlook is not set correctly.

Antivirus blocking connection:-Similarly, Antivirus installed on customer’s PC can sometimes hamper the email functionality. In other words, Antivirus software which includes email scanning feature needs additional configuration to use Outlook together with Antivirus. So, if this is misconfigured, it can block the incoming and outgoing emails.

Outlook Email settings:-Faulty Outlook settings may lead to email errors. To be clear, wrong SMTP host, username/password, SMTP ports, authentication, etc. can badly affect the entire email delivery.

In addition to that, most ISPs block the common SMTP port 25 to reduce spam. So, in such cases, users can’t communicate to the mail server on port 25 and email delivery fails.

How to Fix 0x800ccc0f MS Outlook Error

1. Check Your Internet Connection

It might just be the case that your internet connection is down. So check that websites are opening in your browser. If not, the issue is obviously due to a connection error. Rebooting your router might fix the connection.

2. Switch Off The Windows Firewall

The windows firewall is another thing that can block Microsoft Outlook. So switching the firewall off is one another suitable resolution for Outlook issue 0x800ccc0f. This is how you can configure the Windows Firewall settings in Windows 10.

  1. Click the Cortana button on the taskbar to open that app.
  2. Input the keyword ‘Windows Firewall’ in Cortana’s search box, and then select to open Windows Defender Firewall.
  3. ClickTurn Windows Firewall on or off to open the options shown directly below.
  4. Select both the Turn off Windows Defender Firewall options there, and then press the OK button.
  5. Optionally, you can check if Outlook is allowed through the Windows Firewall by pressing Allow an app or feature through Windows Defender Firewall.
  6. Click the Change settings button, and then move to Outlook in the Allowed apps list.
  7. Select both Outlook‘s checkboxes if they are not ticked.
    • Run the Win + X menu by holding the Win key + X hotkey.
    • Then Hit Run on the Win + X menu to open its window.
    • Enter ‘Outlook /safe’ in Run’s text box and the OK button.
    • A Choose Profiles window will then open.

Press the OK button on that window. Then press the OK button to verify the new settings.

3. Increase The Server Timeouts Setting In Outlook

Outlook comprises a Server Timeouts bar that can set up interrupted connections when you drag it to a longer setting. As such, that is another option worth noting for solving the Outlook issue 0x800ccc0f. This is how to increase the Server Timeouts settings in Outlook 2010.

  1. Open the Outlook software, and then choose the File tab.
  2. Click the Account Settings button and click Account Settings to open the E-mail Accounts window.
  3. Then click on the Change > More Settings buttons to open the E-Mail Settings Tab.
  4. Press the Advanced tab, and then drag the Server Timeouts bar to the far right.
  5. Press the OK button to shut the window.

4. Eliminate All Suspicious Mails From Outlook & Outlook Outbox

At times, suspicious emails or emails with un-trusted attachments may be the actual reason behind this issue. If you get such emails from Outlook inbox then, you have to remove them Quickly. If your MS Outlook outbox gets overcrowded, clean it up.

5. Convert OST File To PST

If the above-mentioned method does not fix the ‘MS Outlook sending receiving issue 0x800ccc0f’ problem, then the most recommended technique would be to convert OST to PST file and then import the exported PST file in MS Outlook. Else, users can go for a reliable third party tool for fixing Outlook related concerns.

How to Choose a Reliable Outlook PST Repair Tool?

First of all, let me introduces a built-in utility provided by Microsoft. The Inbox Repair Tool (called a ScanPST.exe tool) to fix minor corruptions in Outlook PST data files. It’s working simple, that user needs to open ScanPST.exe tool and browse his/ her damaged PST files to scan and repair it manually. But this Inbox repair tool cannot repair highly corrupted PST files. In such cases, it is better to go for trust-able products like SysTools Outlook PST file repair software to repair damaged PST batch without any data loss.


In this article, we have mentioned all the possible reasons behind the occurrence of this error code “0x800ccc0f” and also mentioned the most reliable methods to fix this issue.

Please let us know in the comments section if you are still facing this issue. We will surely help you.

Leave a Reply