How to Fix the Error 0x800ccc0f in Outlook?

The error 0x800CCC0F in Outlook appears while sending or receiving emails. This usually happens when the email client cannot establish or maintain a connection to the mail server. The complete error message may appear as:

"Sending reported error (0x800CCC0F): The connection to the server was interrupted. If the problem continues, contact your server administrator or Internet service provider (ISP)."

The above error message itself indicates connectivity issues between Outlook and the mail server. But there might be other reasons that can cause problems when sending or receiving emails. In this article, we will look into the possible causes behind this Outlook error and the practical approaches to resolve the issue.

Reasons behind the Error 0x800ccc0f in Outlook

Here are some possible reasons that can cause this send/receive error in Outlook.

Poor or Unstable Internet Connection

Outlook requires a stable internet connection to connect with the mail server. If your internet connectivity is unstable or poor, the application may fail to send or receive the emails, causing the error.

Firewall or Antivirus Interference

Security software, such as antivirus, may interfere with Outlook’s functionality, preventing it from sending and receiving emails.  

Corrupted Outlook Profile

If your Outlook profile is damaged or corrupted, then the application nay fail to authenticate with the mail server, leading to the error.

Large Outlook Data File (OST)

If Outlook data (OST) file becomes large or the mailbox gets full, the application cannot download incoming messages or send new emails.

Server Timeout Issue

When the outgoing mail server takes more time to respond than the limit set in settings, then Outlook fails to send the emails.

Damaged or Inconsistent OST File

If your OST file is damaged or inconsistent, Outlook may fail to read the file properly, leading to synchronization issues and failure to send or receive emails.

Methods to Fix Outlook Error 0x800ccc0f

Depending upon the reason behind the error, you can follow the below methods to fix this Outlook send/receive error.

Method 1. Check for Connectivity Issues

Outlook requires a stable network connection to communicate with the email server. The first thing to check is your internet connection. Here’s how you can check if your internet connection is working:

• Open any random website in your web browser and see if it is opening and loading properly.
• Connect your system to another network and then try to send an email in Outlook.

If there is a problem with the internet connection, restart the router or contact your Internet Service Provider (ISP).

If the internet connection is working normally, proceed to the next method.

Method 2. Disable Antivirus Program or Firewall Temporarily

The antivirus program may interfere or block the incoming or outgoing emails in Outlook. To confirm if your security program is causing the issue, you can disable it temporarily.

If you’re using Windows Defender, go to the Windows Security settings on your system and disable the Real-time protection option.

If you’re using any third-party antivirus program (like Kaspersky or AVG), then right-click the icon of your program, select Shut Down Protection or open the settings to turn it off.

After disabling the program, open Outlook and see if you’re getting the error. If yes, then add Outlook and related processes in exclusion list of the program or contact the vendor.

Caution: Turning off your antivirus or firewall will expose your system to security risks. So, disable the program temporarily.

Method 3. Increase the Server Timeout

The Server Timeout setting in Outlook is the maximum time the outgoing mail server waits for a request to complete before dropping it. When the server takes more time for responding than the limit allows in the settings, Outlook fails to send the emails, resulting the error. In this case, you can change the server timeout settings. Here’s how to do so:

• Open Outlook and go to File > Account Settings > Account Settings.
• Select your email account and click Change > More Settings.
• Open the Advanced tab.
• Look for the Server Timeouts option. You can move the slider towards right to increase the value according to your preference.
• Click OK and then restart Outlook.

Method 4. Clear up Suspicious Emails from Outlook

Sometimes, suspicious emails or emails with untrusted attachments might be the real reason behind this error. If you think there are such emails within your Inbox, delete them immediately. Also, if your Outbox is overloaded, clear it up. Then, try sending an email and check if the error is resolved.

Method 5. Verify your Router’s MTU

The Maximum Transmission Unit (MTU) size of your router might also lead to the Outlook error code 0x800ccc0f while sending/receiving particular emails. Check it and make changes to outgoing message sizes accordingly. To get help on this, you may get in touch with your device or router manufacturer's support.

Method 6: Reduce your OST file size

If your OST file gets too large or oversized, you may encounter errors and issues such as email send/receive problems. You can fix this issue by reducing the size of your OST file. You can reduce the OST file size by:

• Using the mailbox cleanup tool to delete unnecessary emails.
• Compacting the OST file.
• Emptying your Deleted Items folder completely.
• Removing redundant messages by using the conversion cleanup feature.
• Archiving your old emails.
• Removing the large attachments.

Method 7. Disable Faulty Add-ins

A faulty or incompatible add-in can sometimes interfere with Outlook’s normal operation and affect its ability to send or receive emails. Starting the application in Safe Mode loads it without add-ins. This helps you to determine whether an add-in is contributing to the error.

To start Outlook in Safe mode, press Windows key + R, type outlook.exe /safe, and hit ‘Enter’ or click ‘OK.’ If it works properly in Safe Mode, an add-in may be causing the problem. In this case, restart Outlook normally and disable the faulty add-ins one at a time to identify the problematic one. Here’s how to do so:

• Open Outlook and go to File tab.
• Choose options at the bottom of the left menu and click Add-ins.

• Select COM Add-ins, and click Go.
• Uncheck all add-ins to disable them and then enable the add-ins one at a time to identify the problematic one.
• Once you find the faulty add-ins, disable and remove them permanently.

Method 8. Create a New Outlook Profile

A damaged or corrupted Outlook profile can prevent the email client from connecting properly to the mail server. To determine whether the profile is causing the error 0x800ccc0f, create a new Outlook profile. Here’s how:

• Close Outlook completely and open Control Panel.
• Click on Mail or Mail (Microsoft Outlook).

• Click on Show Profiles in the setup window.

• Click Add and type a name for your new profile. Click OK.

• Then, enter your email address and password.
• Follow the on-screen prompts and then click Finish.

Method 9. Recreate the OST File

A damaged or inconsistent data (OST) file can cause various errors and issues in Outlook, including problems while sending or receiving emails. You can recreate the OST file after taking its backup. Follow the steps below to recreate the OST file:

• Close Microsoft Outlook completely on your computer.
• Open File Explorer, type %localappdata%\Microsoft\Outlook in the address bar and press Enter.
• Find the .ost file for your email account.
• Delete or rename that file and restart the application.

Outlook will automatically recreate the new OST file at its default location and synchronize all your mailbox data from the server.

Method 10: Convert OST to PST

When the above methods don’t resolve the issue, then there might be a problem with the OST file or it becomes inaccessible. The best solution in this case is to convert the file to PST format by using Stellar Converter for OST. This software can convert all the mailbox items from your inaccessible OST file to PST without altering the folder structure and hierarchy. You can then import the converted PST into your Outlook profile and fix the error.

Wrapping It Up

We’ve mentioned various methods in this article that can help you fix the Outlook send/receive error 0x800ccc0f. If the OST is inaccessible or damaged, then you can use Stellar Converter for OST to recover the mailbox data and save it in PST file format. This OST to PST converter can also save the OST file data in other common file formats, such EML, MSG, etc.