Unexpected Outlook errors can ruin your entire business day.
One such problem is Outlook reported error 0x800ccc0f.
Things were working fine, but why does Outlook suddenly complain about 0x800ccc0f error?
At Bobcares, we resolve lot of such customer queries as part of our Server Support services for web hosts.
Today, we’ll discuss the top 6 reasons for this error and how we fix them.
Outlook reported error 0x800ccc0f – Quick glance
0x800ccc0f is a common error reported by Microsoft Outlook users. This error usually occurs when users attempt to send or receive SMTP based emails but the Outlook can’t connect to the user’s mail server.
And, users see the error message that ‘Connection to the server was interrupted’ or ‘Your server has unexpectedly terminated the connection’ along with the error code.
For instance, the complete error message looks like this:
Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: mail.domain.com, Server: 'mail.domain.com', Protocol: POP3, Server Response: '+OK', Port: 110, Secure(SSL): N0, Error Number: 0x800ccc0f
Outlook reported error 0x800ccc0f – Causes & Fixes
Now, let’s see the common causes of this error and how our Server Support Engineers fix them.
1) Server firewall restrictions
This can usually happen when 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 user’s access, they will see Outlook reported error 0x800ccc0f.
Solution
Firstly, our Hosting Engineers verify whether the user’s IP address is blocked in the server firewall. For example, we use the following command to check the IP block on cPanel servers.
csf -g xx.xx.xx.xx
If it’s listed, we remove it and restore the email connectivity immediately. After that, we identify the cause of the block and update the users.
For instance, we use the following command to remove the IP block on cPanel servers.
csf -dr xx.xx.xx.xx[Worried about messed up firewall rules on your server? Click here to get one of our experienced Server Experts to fix this issue.]
2) Customer’s local firewall settings
Likewise, customer’s local firewall can sometimes block incoming and outgoing emails. That is, this error can occur if the custom SMTP port is not added in firewall or if the priority of Microsoft Outlook is set incorrectly.
Solution
In such cases, our Support Engineers temporary disable the security applications(windows firewall, software firewall) one by one. So that, we can determine which application causes the error and fix the settings.
For example in Windows server, you can disable the firewall from Start > Control Panel > Network Connections > Properties > Security > Windows firewall.
3) 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.
Solution
Our Support Experts ask customers to temporarily disable the Antivirus on their system. This helps us to figure out if Antivirus is blocking the connections.
4) 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.
Solution
Here we get the customer’s basic Outlook settings and make sure they’re correct. We also check the server timeout settings in Outlook as well.
In addition to that, we check the traceroute results from user’s PC to the mail server. This helps us to identify intermediate network connectivity problems between the mail server and user’s PC. If we find problems at the ISP end, we suggest customers to contact them.
Alternatively, we set up mail server on alternate ports such as 587 to override ISP port blocks and ask the customer to change the SMTP setting from 25 to 587.
Apart from this, we help customers clear suspicious emails or emails with untrusted attachments. Additionally, we delete the unsent messages stuck in the Outbox.
5) Corrupted Outlook profile
Outlook profile is used to remember the email accounts established with it and the settings that tell where the email and other data is stored. A faulty Outlook profile may also result in the error 0x800ccc0f.
Solution
In such cases, we assist customers create a new profile and test whether they can send/receive emails using this profile. If it works, we help customers remove the default profile and set the new one as the default Outlook profile.
Alternatively, we execute Outlook in Safe mode and disable the unnecessary utilities in the Outlook profile.
6) Corrupted Outlook PST files
This can happen at times.
Outlook error 0x800ccc0f may be caused by corrupted Outlook data files(PST and OST). Outlook uses the PST files to connect to the server and perform email transactions.
But, when these dependencies get corrupted, it leads to a connection failure leading to this error.
Solution
In this case the only solution is to repair the corrupted PST files.
For minor corruptions, our Hosting Engineers recommend customers to use built-in repair tools like Inbox Repair Tool, OST Integrity Check tool, etc. to fix the PST files.
On the other hand, in case of major corruptions we suggest customers to use third party repair tools to repair the corrupted PST files without any data loss.
[And, do you need a Support Expert to look into this error? One of our Support Engineers can help you here.]
Conclusion
In short, Outlook reported error 0x800ccc0f can occur due to server firewall restrictions, local firewall, antivirus, and more. Today, we’ve discussed the top 6 reasons for this error and how our Server Support Engineers fix them.
Beat my head against this until yesterday. Problem was stuck read receipts. Used MFCMAPI.exe to fix. Instructions available with quick web search. Outlook 2016.